diff --git a/.maintain/rename-crates-for-2.0.sh b/.maintain/rename-crates-for-2.0.sh
index d2bd871f09780..b024cfd4418c6 100644
--- a/.maintain/rename-crates-for-2.0.sh
+++ b/.maintain/rename-crates-for-2.0.sh
@@ -43,6 +43,7 @@ TO_RENAME=(
     "sp-finality-granpda sp-finality-grandpa"
     "sp-sesssion sp-session"
     "sp-tracing-pool sp-transaction-pool"
+    "sc-basic-authority sc-basic-authorship"
 
     # PRIMITIVES
     "substrate-application-crypto sp-application-crypto"
@@ -88,7 +89,7 @@ TO_RENAME=(
     "substrate-client sc-client"
     "substrate-client-api sc-api"
     "substrate-authority-discovery sc-authority-discovery"
-    "substrate-basic-authorship sc-basic-authority"
+    "substrate-basic-authorship sc-basic-authorship"
     "substrate-block-builder sc-block-builder"
     "substrate-chain-spec sc-chain-spec"
     "substrate-chain-spec-derive sc-chain-spec-derive"
diff --git a/Cargo.lock b/Cargo.lock
index 60a7a4e1ad20f..b8df759cf4087 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -371,7 +371,7 @@ dependencies = [
 
 [[package]]
 name = "browser-utils"
-version = "2.0.0"
+version = "0.8.0"
 dependencies = [
  "clear_on_drop 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "console_error_panic_hook 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -386,7 +386,7 @@ dependencies = [
  "rand 0.7.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "sc-chain-spec 2.0.0",
  "sc-network 0.8.0",
- "sc-service 2.0.0",
+ "sc-service 0.8.0",
  "wasm-bindgen 0.2.57 (registry+https://github.com/rust-lang/crates.io-index)",
  "wasm-bindgen-futures 0.4.7 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -1087,7 +1087,7 @@ dependencies = [
 
 [[package]]
 name = "environmental"
-version = "1.0.2"
+version = "1.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
@@ -1231,13 +1231,13 @@ dependencies = [
 
 [[package]]
 name = "finality-grandpa"
-version = "0.10.2"
+version = "0.10.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "futures 0.1.29 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "num-traits 0.2.10 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -1249,7 +1249,7 @@ dependencies = [
  "byteorder 1.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand 0.7.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-hex 2.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-hex 2.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "static_assertions 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -1292,7 +1292,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 name = "fork-tree"
 version = "2.0.0"
 dependencies = [
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -1305,7 +1305,7 @@ dependencies = [
  "pallet-balances 2.0.0",
  "pallet-indices 2.0.0",
  "pallet-transaction-payment 2.0.0",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-core 2.0.0",
  "sp-io 2.0.0",
@@ -1315,9 +1315,9 @@ dependencies = [
 
 [[package]]
 name = "frame-metadata"
-version = "2.0.0"
+version = "10.0.0"
 dependencies = [
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-core 2.0.0",
  "sp-std 2.0.0",
@@ -1328,13 +1328,13 @@ name = "frame-support"
 version = "2.0.0"
 dependencies = [
  "bitmask 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "frame-metadata 2.0.0",
+ "frame-metadata 10.0.0",
  "frame-support-procedural 2.0.0",
  "frame-system 2.0.0",
  "impl-trait-for-tuples 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "once_cell 0.2.4 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "paste 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "pretty_assertions 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1343,7 +1343,7 @@ dependencies = [
  "sp-inherents 2.0.0",
  "sp-io 2.0.0",
  "sp-runtime 2.0.0",
- "sp-state-machine 2.0.0",
+ "sp-state-machine 0.8.0",
  "sp-std 2.0.0",
  "tracing 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -1383,14 +1383,14 @@ name = "frame-support-test"
 version = "2.0.0"
 dependencies = [
  "frame-support 2.0.0",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "pretty_assertions 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-core 2.0.0",
  "sp-inherents 2.0.0",
  "sp-io 2.0.0",
  "sp-runtime 2.0.0",
- "sp-state-machine 2.0.0",
+ "sp-state-machine 0.8.0",
  "trybuild 1.0.18 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -1401,21 +1401,22 @@ dependencies = [
  "criterion 0.2.11 (registry+https://github.com/rust-lang/crates.io-index)",
  "frame-support 2.0.0",
  "impl-trait-for-tuples 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "safe-mix 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-core 2.0.0",
+ "sp-externalities 0.8.0",
  "sp-io 2.0.0",
  "sp-runtime 2.0.0",
  "sp-std 2.0.0",
  "sp-version 2.0.0",
+ "substrate-test-runtime-client 2.0.0",
 ]
 
 [[package]]
 name = "frame-system-rpc-runtime-api"
 version = "2.0.0"
 dependencies = [
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-api 2.0.0",
 ]
 
@@ -2013,7 +2014,7 @@ name = "impl-codec"
 version = "0.4.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -2827,7 +2828,7 @@ dependencies = [
 
 [[package]]
 name = "memory-db"
-version = "0.18.0"
+version = "0.18.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "ahash 0.2.18 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2992,11 +2993,10 @@ dependencies = [
 name = "node-cli"
 version = "2.0.0"
 dependencies = [
- "browser-utils 2.0.0",
+ "browser-utils 0.8.0",
  "ctrlc 3.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "frame-support 2.0.0",
  "frame-system 2.0.0",
- "futures 0.1.29 (registry+https://github.com/rust-lang/crates.io-index)",
  "futures 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "hex-literal 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "jsonrpc-core 14.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -3005,7 +3005,7 @@ dependencies = [
  "node-primitives 2.0.0",
  "node-rpc 2.0.0",
  "node-runtime 2.0.0",
- "node-transaction-factory 2.0.0",
+ "node-transaction-factory 0.8.0",
  "pallet-authority-discovery 2.0.0",
  "pallet-balances 2.0.0",
  "pallet-contracts 2.0.0",
@@ -3013,22 +3013,22 @@ dependencies = [
  "pallet-indices 2.0.0",
  "pallet-timestamp 2.0.0",
  "pallet-transaction-payment 2.0.0",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand 0.7.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "sc-authority-discovery 2.0.0",
- "sc-basic-authority 2.0.0",
+ "sc-authority-discovery 0.8.0",
+ "sc-basic-authorship 0.8.0",
  "sc-chain-spec 2.0.0",
- "sc-cli 2.0.0",
- "sc-client 2.0.0",
+ "sc-cli 0.8.0",
+ "sc-client 0.8.0",
  "sc-client-api 2.0.0",
- "sc-client-db 2.0.0",
+ "sc-client-db 0.8.0",
  "sc-consensus-babe 0.8.0",
- "sc-finality-grandpa 2.0.0",
+ "sc-finality-grandpa 0.8.0",
  "sc-keystore 2.0.0",
  "sc-network 0.8.0",
  "sc-offchain 2.0.0",
  "sc-rpc 2.0.0",
- "sc-service 2.0.0",
+ "sc-service 0.8.0",
  "sc-service-test 2.0.0",
  "sc-telemetry 2.0.0",
  "sc-transaction-pool 2.0.0",
@@ -3048,7 +3048,7 @@ dependencies = [
  "structopt 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "substrate-build-script-utils 2.0.0",
  "tempfile 3.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "tokio 0.1.22 (registry+https://github.com/rust-lang/crates.io-index)",
+ "tokio 0.2.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "vergen 3.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "wasm-bindgen 0.2.57 (registry+https://github.com/rust-lang/crates.io-index)",
  "wasm-bindgen-futures 0.4.7 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -3073,13 +3073,13 @@ dependencies = [
  "pallet-timestamp 2.0.0",
  "pallet-transaction-payment 2.0.0",
  "pallet-treasury 2.0.0",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "sc-executor 2.0.0",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "sc-executor 0.8.0",
  "sp-application-crypto 2.0.0",
  "sp-core 2.0.0",
  "sp-io 2.0.0",
  "sp-runtime 2.0.0",
- "sp-state-machine 2.0.0",
+ "sp-state-machine 0.8.0",
  "sp-trie 2.0.0",
  "substrate-test-client 2.0.0",
  "trie-root 0.15.2 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -3103,9 +3103,9 @@ dependencies = [
  "jsonrpc-core 14.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "node-primitives 2.0.0",
  "node-runtime 2.0.0",
- "pallet-contracts-rpc 2.0.0",
+ "pallet-contracts-rpc 0.8.0",
  "pallet-transaction-payment-rpc 2.0.0",
- "sc-client 2.0.0",
+ "sc-client 0.8.0",
  "sp-api 2.0.0",
  "sp-runtime 2.0.0",
  "sp-transaction-pool 2.0.0",
@@ -3141,18 +3141,20 @@ dependencies = [
  "pallet-balances 2.0.0",
  "pallet-collective 2.0.0",
  "pallet-contracts 2.0.0",
- "pallet-contracts-rpc-runtime-api 2.0.0",
+ "pallet-contracts-rpc-runtime-api 0.8.0",
  "pallet-democracy 2.0.0",
  "pallet-elections-phragmen 2.0.0",
  "pallet-finality-tracker 2.0.0",
  "pallet-grandpa 2.0.0",
+ "pallet-identity 2.0.0",
  "pallet-im-online 2.0.0",
  "pallet-indices 2.0.0",
  "pallet-membership 2.0.0",
- "pallet-nicks 2.0.0",
  "pallet-offences 2.0.0",
  "pallet-randomness-collective-flip 2.0.0",
+ "pallet-recovery 2.0.0",
  "pallet-session 2.0.0",
+ "pallet-society 2.0.0",
  "pallet-staking 2.0.0",
  "pallet-staking-reward-curve 2.0.0",
  "pallet-sudo 2.0.0",
@@ -3161,9 +3163,8 @@ dependencies = [
  "pallet-transaction-payment-rpc-runtime-api 2.0.0",
  "pallet-treasury 2.0.0",
  "pallet-utility 2.0.0",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-hex 2.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "safe-mix 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-hex 2.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-api 2.0.0",
  "sp-authority-discovery 2.0.0",
@@ -3188,20 +3189,19 @@ name = "node-template"
 version = "2.0.0"
 dependencies = [
  "ctrlc 3.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "futures 0.1.29 (registry+https://github.com/rust-lang/crates.io-index)",
  "futures 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "node-template-runtime 2.0.0",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "sc-basic-authority 2.0.0",
- "sc-cli 2.0.0",
- "sc-client 2.0.0",
+ "sc-basic-authorship 0.8.0",
+ "sc-cli 0.8.0",
+ "sc-client 0.8.0",
  "sc-consensus-aura 0.8.0",
- "sc-executor 2.0.0",
- "sc-finality-grandpa 2.0.0",
+ "sc-executor 0.8.0",
+ "sc-finality-grandpa 0.8.0",
  "sc-network 0.8.0",
- "sc-service 2.0.0",
+ "sc-service 0.8.0",
  "sc-transaction-pool 2.0.0",
  "sp-consensus 0.8.0",
  "sp-consensus-aura 0.8.0",
@@ -3212,7 +3212,7 @@ dependencies = [
  "sp-runtime 2.0.0",
  "sp-transaction-pool 2.0.0",
  "substrate-build-script-utils 2.0.0",
- "tokio 0.1.22 (registry+https://github.com/rust-lang/crates.io-index)",
+ "tokio 0.2.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "trie-root 0.15.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "vergen 3.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -3232,8 +3232,7 @@ dependencies = [
  "pallet-sudo 2.0.0",
  "pallet-timestamp 2.0.0",
  "pallet-transaction-payment 2.0.0",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "safe-mix 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-api 2.0.0",
  "sp-block-builder 2.0.0",
@@ -3264,13 +3263,14 @@ dependencies = [
  "pallet-grandpa 2.0.0",
  "pallet-indices 2.0.0",
  "pallet-session 2.0.0",
+ "pallet-society 2.0.0",
  "pallet-staking 2.0.0",
  "pallet-timestamp 2.0.0",
  "pallet-transaction-payment 2.0.0",
  "pallet-treasury 2.0.0",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "sc-client 2.0.0",
- "sc-executor 2.0.0",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "sc-client 0.8.0",
+ "sc-executor 0.8.0",
  "sp-core 2.0.0",
  "sp-io 2.0.0",
  "sp-keyring 2.0.0",
@@ -3281,14 +3281,14 @@ dependencies = [
 
 [[package]]
 name = "node-transaction-factory"
-version = "2.0.0"
+version = "0.8.0"
 dependencies = [
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "sc-cli 2.0.0",
- "sc-client 2.0.0",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "sc-cli 0.8.0",
+ "sc-client 0.8.0",
  "sc-client-api 2.0.0",
- "sc-service 2.0.0",
+ "sc-service 0.8.0",
  "sp-api 2.0.0",
  "sp-block-builder 2.0.0",
  "sp-blockchain 2.0.0",
@@ -3452,7 +3452,7 @@ version = "2.0.0"
 dependencies = [
  "frame-support 2.0.0",
  "frame-system 2.0.0",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-core 2.0.0",
  "sp-io 2.0.0",
@@ -3469,7 +3469,7 @@ dependencies = [
  "lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "pallet-session 2.0.0",
  "pallet-timestamp 2.0.0",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-application-crypto 2.0.0",
@@ -3489,7 +3489,7 @@ dependencies = [
  "frame-support 2.0.0",
  "frame-system 2.0.0",
  "pallet-session 2.0.0",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-application-crypto 2.0.0",
  "sp-authority-discovery 2.0.0",
@@ -3507,7 +3507,7 @@ dependencies = [
  "frame-support 2.0.0",
  "frame-system 2.0.0",
  "impl-trait-for-tuples 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-authorship 2.0.0",
  "sp-core 2.0.0",
  "sp-inherents 2.0.0",
@@ -3526,7 +3526,7 @@ dependencies = [
  "lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "pallet-session 2.0.0",
  "pallet-timestamp 2.0.0",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-consensus-babe 0.8.0",
@@ -3548,8 +3548,7 @@ dependencies = [
  "frame-support 2.0.0",
  "frame-system 2.0.0",
  "pallet-transaction-payment 2.0.0",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "safe-mix 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-core 2.0.0",
  "sp-io 2.0.0",
@@ -3565,8 +3564,7 @@ dependencies = [
  "frame-system 2.0.0",
  "hex-literal 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "pallet-balances 2.0.0",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "safe-mix 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-core 2.0.0",
  "sp-io 2.0.0",
@@ -3585,14 +3583,14 @@ dependencies = [
  "pallet-balances 2.0.0",
  "pallet-randomness-collective-flip 2.0.0",
  "pallet-timestamp 2.0.0",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "parity-wasm 0.41.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "pwasm-utils 0.12.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-core 2.0.0",
  "sp-io 2.0.0",
  "sp-runtime 2.0.0",
- "sp-sandbox 2.0.0",
+ "sp-sandbox 0.8.0",
  "sp-std 2.0.0",
  "wabt 0.9.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "wasmi-validation 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -3600,13 +3598,13 @@ dependencies = [
 
 [[package]]
 name = "pallet-contracts-rpc"
-version = "2.0.0"
+version = "0.8.0"
 dependencies = [
  "jsonrpc-core 14.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "jsonrpc-core-client 14.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "jsonrpc-derive 14.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
- "pallet-contracts-rpc-runtime-api 2.0.0",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "pallet-contracts-rpc-runtime-api 0.8.0",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_json 1.0.44 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-api 2.0.0",
@@ -3618,9 +3616,9 @@ dependencies = [
 
 [[package]]
 name = "pallet-contracts-rpc-runtime-api"
-version = "2.0.0"
+version = "0.8.0"
 dependencies = [
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-api 2.0.0",
  "sp-runtime 2.0.0",
  "sp-std 2.0.0",
@@ -3633,8 +3631,7 @@ dependencies = [
  "frame-support 2.0.0",
  "frame-system 2.0.0",
  "pallet-balances 2.0.0",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "safe-mix 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-core 2.0.0",
  "sp-io 2.0.0",
@@ -3650,8 +3647,7 @@ dependencies = [
  "frame-system 2.0.0",
  "hex-literal 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "pallet-balances 2.0.0",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "safe-mix 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-core 2.0.0",
  "sp-io 2.0.0",
@@ -3667,7 +3663,7 @@ dependencies = [
  "frame-system 2.0.0",
  "hex-literal 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "pallet-balances 2.0.0",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-core 2.0.0",
  "sp-io 2.0.0",
@@ -3686,7 +3682,7 @@ dependencies = [
  "frame-system 2.0.0",
  "pallet-balances 2.0.0",
  "pallet-timestamp 2.0.0",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "primitive-types 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "rlp 0.4.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -3704,7 +3700,7 @@ dependencies = [
  "frame-support 2.0.0",
  "frame-system 2.0.0",
  "pallet-balances 2.0.0",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-core 2.0.0",
  "sp-io 2.0.0",
@@ -3719,7 +3715,7 @@ dependencies = [
  "frame-support 2.0.0",
  "frame-system 2.0.0",
  "impl-trait-for-tuples 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-core 2.0.0",
  "sp-finality-tracker 2.0.0",
@@ -3735,7 +3731,7 @@ version = "2.0.0"
 dependencies = [
  "frame-support 2.0.0",
  "frame-system 2.0.0",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-core 2.0.0",
  "sp-io 2.0.0",
@@ -3751,7 +3747,7 @@ dependencies = [
  "frame-system 2.0.0",
  "pallet-finality-tracker 2.0.0",
  "pallet-session 2.0.0",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-core 2.0.0",
  "sp-finality-grandpa 2.0.0",
@@ -3769,7 +3765,7 @@ dependencies = [
  "frame-support 2.0.0",
  "frame-system 2.0.0",
  "pallet-balances 2.0.0",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-core 2.0.0",
  "sp-io 2.0.0",
@@ -3785,7 +3781,7 @@ dependencies = [
  "frame-system 2.0.0",
  "pallet-authorship 2.0.0",
  "pallet-session 2.0.0",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-application-crypto 2.0.0",
  "sp-core 2.0.0",
@@ -3801,8 +3797,7 @@ version = "2.0.0"
 dependencies = [
  "frame-support 2.0.0",
  "frame-system 2.0.0",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "safe-mix 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-core 2.0.0",
  "sp-io 2.0.0",
@@ -3817,7 +3812,7 @@ version = "2.0.0"
 dependencies = [
  "frame-support 2.0.0",
  "frame-system 2.0.0",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-core 2.0.0",
  "sp-io 2.0.0",
@@ -3832,7 +3827,7 @@ dependencies = [
  "frame-support 2.0.0",
  "frame-system 2.0.0",
  "pallet-balances 2.0.0",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-core 2.0.0",
  "sp-io 2.0.0",
@@ -3847,7 +3842,7 @@ dependencies = [
  "frame-support 2.0.0",
  "frame-system 2.0.0",
  "pallet-balances 2.0.0",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-core 2.0.0",
  "sp-io 2.0.0",
@@ -3862,7 +3857,7 @@ version = "2.0.0"
 dependencies = [
  "frame-support 2.0.0",
  "frame-system 2.0.0",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "safe-mix 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-core 2.0.0",
  "sp-io 2.0.0",
@@ -3878,7 +3873,7 @@ dependencies = [
  "frame-support 2.0.0",
  "frame-system 2.0.0",
  "pallet-balances 2.0.0",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-core 2.0.0",
  "sp-io 2.0.0",
@@ -3893,7 +3888,7 @@ dependencies = [
  "frame-support 2.0.0",
  "frame-system 2.0.0",
  "pallet-balances 2.0.0",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-core 2.0.0",
  "sp-io 2.0.0",
@@ -3910,8 +3905,7 @@ dependencies = [
  "impl-trait-for-tuples 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "pallet-timestamp 2.0.0",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "safe-mix 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-application-crypto 2.0.0",
  "sp-core 2.0.0",
@@ -3929,7 +3923,7 @@ dependencies = [
  "frame-support 2.0.0",
  "frame-system 2.0.0",
  "pallet-balances 2.0.0",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand_chacha 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-core 2.0.0",
@@ -3949,8 +3943,7 @@ dependencies = [
  "pallet-session 2.0.0",
  "pallet-staking-reward-curve 2.0.0",
  "pallet-timestamp 2.0.0",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "safe-mix 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-core 2.0.0",
  "sp-io 2.0.0",
@@ -3979,7 +3972,7 @@ version = "2.0.0"
 dependencies = [
  "frame-support 2.0.0",
  "frame-system 2.0.0",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-core 2.0.0",
  "sp-io 2.0.0",
@@ -3994,7 +3987,7 @@ dependencies = [
  "frame-support 2.0.0",
  "frame-system 2.0.0",
  "impl-trait-for-tuples 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-core 2.0.0",
  "sp-inherents 2.0.0",
@@ -4012,7 +4005,7 @@ dependencies = [
  "frame-system 2.0.0",
  "pallet-balances 2.0.0",
  "pallet-transaction-payment-rpc-runtime-api 2.0.0",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-core 2.0.0",
  "sp-io 2.0.0",
  "sp-runtime 2.0.0",
@@ -4027,7 +4020,7 @@ dependencies = [
  "jsonrpc-core-client 14.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "jsonrpc-derive 14.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "pallet-transaction-payment-rpc-runtime-api 2.0.0",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-api 2.0.0",
  "sp-blockchain 2.0.0",
@@ -4041,7 +4034,7 @@ name = "pallet-transaction-payment-rpc-runtime-api"
 version = "2.0.0"
 dependencies = [
  "frame-support 2.0.0",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_json 1.0.44 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-api 2.0.0",
@@ -4056,7 +4049,7 @@ dependencies = [
  "frame-support 2.0.0",
  "frame-system 2.0.0",
  "pallet-balances 2.0.0",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-core 2.0.0",
  "sp-io 2.0.0",
@@ -4071,7 +4064,7 @@ dependencies = [
  "frame-support 2.0.0",
  "frame-system 2.0.0",
  "pallet-balances 2.0.0",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-core 2.0.0",
  "sp-io 2.0.0",
@@ -4148,7 +4141,7 @@ dependencies = [
 
 [[package]]
 name = "parity-scale-codec"
-version = "1.1.0"
+version = "1.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "arrayvec 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -4500,8 +4493,8 @@ dependencies = [
 ]
 
 [[package]]
-name = "prometheus-endpoint"
-version = "2.0.0"
+name = "prometheus-exporter"
+version = "0.8.0"
 dependencies = [
  "async-std 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "derive_more 0.99.2 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -4917,7 +4910,7 @@ name = "rlp"
 version = "0.4.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "rustc-hex 2.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-hex 2.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -4955,7 +4948,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "rustc-hex"
-version = "2.0.1"
+version = "2.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
@@ -5033,7 +5026,7 @@ dependencies = [
 
 [[package]]
 name = "sc-authority-discovery"
-version = "2.0.0"
+version = "0.8.0"
 dependencies = [
  "bytes 0.4.12 (registry+https://github.com/rust-lang/crates.io-index)",
  "derive_more 0.99.2 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -5042,7 +5035,7 @@ dependencies = [
  "futures-timer 2.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "libp2p 0.14.0-alpha.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "prost 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "prost-build 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "quickcheck 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -5061,15 +5054,15 @@ dependencies = [
 ]
 
 [[package]]
-name = "sc-basic-authority"
-version = "2.0.0"
+name = "sc-basic-authorship"
+version = "0.8.0"
 dependencies = [
  "futures 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "sc-block-builder 2.0.0",
- "sc-client 2.0.0",
+ "sc-block-builder 0.8.0",
+ "sc-client 0.8.0",
  "sc-client-api 2.0.0",
  "sc-telemetry 2.0.0",
  "sc-transaction-pool 2.0.0",
@@ -5086,9 +5079,9 @@ dependencies = [
 
 [[package]]
 name = "sc-block-builder"
-version = "2.0.0"
+version = "0.8.0"
 dependencies = [
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "sc-client-api 2.0.0",
  "sp-api 2.0.0",
  "sp-block-builder 2.0.0",
@@ -5096,7 +5089,7 @@ dependencies = [
  "sp-consensus 0.8.0",
  "sp-core 2.0.0",
  "sp-runtime 2.0.0",
- "sp-state-machine 2.0.0",
+ "sp-state-machine 0.8.0",
 ]
 
 [[package]]
@@ -5125,7 +5118,7 @@ dependencies = [
 
 [[package]]
 name = "sc-cli"
-version = "2.0.0"
+version = "0.8.0"
 dependencies = [
  "ansi_term 0.12.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "app_dirs 1.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -5138,12 +5131,12 @@ dependencies = [
  "lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "names 0.11.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "prometheus-endpoint 2.0.0",
+ "prometheus-exporter 0.8.0",
  "regex 1.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "rpassword 4.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "sc-client-api 2.0.0",
  "sc-network 0.8.0",
- "sc-service 2.0.0",
+ "sc-service 0.8.0",
  "sc-telemetry 2.0.0",
  "sc-tracing 2.0.0",
  "serde_json 1.0.44 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -5152,7 +5145,7 @@ dependencies = [
  "sp-keyring 2.0.0",
  "sp-panic-handler 2.0.0",
  "sp-runtime 2.0.0",
- "sp-state-machine 2.0.0",
+ "sp-state-machine 0.8.0",
  "structopt 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "tempfile 3.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "time 0.1.42 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -5161,7 +5154,7 @@ dependencies = [
 
 [[package]]
 name = "sc-client"
-version = "2.0.0"
+version = "0.8.0"
 dependencies = [
  "derive_more 0.99.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "env_logger 0.7.1 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -5172,22 +5165,22 @@ dependencies = [
  "kvdb 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "kvdb-memorydb 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "sc-block-builder 2.0.0",
+ "sc-block-builder 0.8.0",
  "sc-client-api 2.0.0",
- "sc-executor 2.0.0",
+ "sc-executor 0.8.0",
  "sc-telemetry 2.0.0",
  "sp-api 2.0.0",
  "sp-blockchain 2.0.0",
  "sp-consensus 0.8.0",
  "sp-core 2.0.0",
- "sp-externalities 2.0.0",
+ "sp-externalities 0.8.0",
  "sp-inherents 2.0.0",
  "sp-keyring 2.0.0",
  "sp-panic-handler 2.0.0",
  "sp-runtime 2.0.0",
- "sp-state-machine 2.0.0",
+ "sp-state-machine 0.8.0",
  "sp-std 2.0.0",
  "sp-trie 2.0.0",
  "sp-version 2.0.0",
@@ -5207,19 +5200,19 @@ dependencies = [
  "hex-literal 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "kvdb 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "sc-executor 2.0.0",
+ "sc-executor 0.8.0",
  "sc-telemetry 2.0.0",
  "sp-api 2.0.0",
  "sp-blockchain 2.0.0",
  "sp-consensus 0.8.0",
  "sp-core 2.0.0",
- "sp-externalities 2.0.0",
+ "sp-externalities 0.8.0",
  "sp-inherents 2.0.0",
  "sp-keyring 2.0.0",
  "sp-runtime 2.0.0",
- "sp-state-machine 2.0.0",
+ "sp-state-machine 0.8.0",
  "sp-std 2.0.0",
  "sp-test-primitives 2.0.0",
  "sp-transaction-pool 2.0.0",
@@ -5229,7 +5222,7 @@ dependencies = [
 
 [[package]]
 name = "sc-client-db"
-version = "2.0.0"
+version = "0.8.0"
 dependencies = [
  "env_logger 0.7.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "hash-db 0.15.2 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -5238,22 +5231,23 @@ dependencies = [
  "kvdb-rocksdb 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "linked-hash-map 0.5.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "parity-util-mem 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "quickcheck 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "sc-client 2.0.0",
+ "sc-client 0.8.0",
  "sc-client-api 2.0.0",
- "sc-executor 2.0.0",
- "sc-state-db 2.0.0",
+ "sc-executor 0.8.0",
+ "sc-state-db 0.8.0",
  "sp-blockchain 2.0.0",
  "sp-consensus 0.8.0",
  "sp-core 2.0.0",
  "sp-keyring 2.0.0",
  "sp-runtime 2.0.0",
- "sp-state-machine 2.0.0",
+ "sp-state-machine 0.8.0",
  "sp-trie 2.0.0",
  "substrate-test-runtime-client 2.0.0",
+ "tempdir 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -5266,16 +5260,16 @@ dependencies = [
  "futures 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "futures-timer 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "sc-client 2.0.0",
+ "sc-client 0.8.0",
  "sc-client-api 2.0.0",
  "sc-consensus-slots 0.8.0",
- "sc-executor 2.0.0",
+ "sc-executor 0.8.0",
  "sc-keystore 2.0.0",
  "sc-network 0.8.0",
- "sc-network-test 2.0.0",
- "sc-service 2.0.0",
+ "sc-network-test 0.8.0",
+ "sc-service 0.8.0",
  "sc-telemetry 2.0.0",
  "sp-api 2.0.0",
  "sp-application-crypto 2.0.0",
@@ -5310,20 +5304,20 @@ dependencies = [
  "num-bigint 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "num-rational 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "num-traits 0.2.10 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "pdqselect 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand 0.7.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "sc-block-builder 2.0.0",
- "sc-client 2.0.0",
+ "sc-block-builder 0.8.0",
+ "sc-client 0.8.0",
  "sc-client-api 2.0.0",
  "sc-consensus-slots 0.8.0",
  "sc-consensus-uncles 0.8.0",
- "sc-executor 2.0.0",
+ "sc-executor 0.8.0",
  "sc-keystore 2.0.0",
  "sc-network 0.8.0",
- "sc-network-test 2.0.0",
- "sc-service 2.0.0",
+ "sc-network-test 0.8.0",
+ "sc-service 0.8.0",
  "sc-telemetry 2.0.0",
  "schnorrkel 0.8.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-api 2.0.0",
@@ -5351,7 +5345,7 @@ dependencies = [
  "derive_more 0.99.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "futures 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "sc-client-api 2.0.0",
  "sp-api 2.0.0",
  "sp-block-builder 2.0.0",
@@ -5371,7 +5365,7 @@ dependencies = [
  "futures 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "futures-timer 2.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "sc-client-api 2.0.0",
  "sc-telemetry 2.0.0",
@@ -5381,7 +5375,7 @@ dependencies = [
  "sp-core 2.0.0",
  "sp-inherents 2.0.0",
  "sp-runtime 2.0.0",
- "sp-state-machine 2.0.0",
+ "sp-state-machine 0.8.0",
  "substrate-test-runtime-client 2.0.0",
 ]
 
@@ -5400,7 +5394,7 @@ dependencies = [
 
 [[package]]
 name = "sc-executor"
-version = "2.0.0"
+version = "0.8.0"
 dependencies = [
  "assert_matches 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "derive_more 0.99.2 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -5408,20 +5402,20 @@ dependencies = [
  "lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "libsecp256k1 0.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "parity-wasm 0.41.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "sc-executor-common 2.0.0",
- "sc-executor-wasmi 2.0.0",
- "sc-executor-wasmtime 2.0.0",
+ "sc-executor-common 0.8.0",
+ "sc-executor-wasmi 0.8.0",
+ "sc-executor-wasmtime 0.8.0",
  "sc-runtime-test 2.0.0",
  "sp-core 2.0.0",
- "sp-externalities 2.0.0",
+ "sp-externalities 0.8.0",
  "sp-io 2.0.0",
  "sp-panic-handler 2.0.0",
  "sp-runtime-interface 2.0.0",
  "sp-serializer 2.0.0",
- "sp-state-machine 2.0.0",
+ "sp-state-machine 0.8.0",
  "sp-trie 2.0.0",
  "sp-version 2.0.0",
  "sp-wasm-interface 2.0.0",
@@ -5433,11 +5427,11 @@ dependencies = [
 
 [[package]]
 name = "sc-executor-common"
-version = "2.0.0"
+version = "0.8.0"
 dependencies = [
  "derive_more 0.99.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-core 2.0.0",
  "sp-runtime-interface 2.0.0",
  "sp-serializer 2.0.0",
@@ -5447,14 +5441,13 @@ dependencies = [
 
 [[package]]
 name = "sc-executor-wasmi"
-version = "2.0.0"
+version = "0.8.0"
 dependencies = [
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "parity-wasm 0.41.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "sc-executor-common 2.0.0",
+ "sc-executor-common 0.8.0",
  "sp-core 2.0.0",
- "sp-externalities 2.0.0",
  "sp-runtime-interface 2.0.0",
  "sp-wasm-interface 2.0.0",
  "wasmi 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -5462,7 +5455,7 @@ dependencies = [
 
 [[package]]
 name = "sc-executor-wasmtime"
-version = "2.0.0"
+version = "0.8.0"
 dependencies = [
  "assert_matches 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "cranelift-codegen 0.50.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -5471,11 +5464,10 @@ dependencies = [
  "cranelift-native 0.50.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "cranelift-wasm 0.50.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "parity-wasm 0.41.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "sc-executor-common 2.0.0",
+ "sc-executor-common 0.8.0",
  "sp-core 2.0.0",
- "sp-externalities 2.0.0",
  "sp-runtime-interface 2.0.0",
  "sp-wasm-interface 2.0.0",
  "wasmi 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -5486,27 +5478,28 @@ dependencies = [
 
 [[package]]
 name = "sc-finality-grandpa"
-version = "2.0.0"
+version = "0.8.0"
 dependencies = [
  "env_logger 0.7.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "finality-grandpa 0.10.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "finality-grandpa 0.10.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "fork-tree 2.0.0",
  "futures 0.1.29 (registry+https://github.com/rust-lang/crates.io-index)",
  "futures 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "futures-timer 2.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand 0.7.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "sc-client 2.0.0",
+ "sc-client 0.8.0",
  "sc-client-api 2.0.0",
  "sc-keystore 2.0.0",
  "sc-network 0.8.0",
- "sc-network-gossip 2.0.0",
- "sc-network-test 2.0.0",
+ "sc-network-gossip 0.8.0",
+ "sc-network-test 0.8.0",
  "sc-telemetry 2.0.0",
  "serde_json 1.0.44 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-api 2.0.0",
+ "sp-arithmetic 2.0.0",
  "sp-blockchain 2.0.0",
  "sp-consensus 0.8.0",
  "sp-consensus-babe 0.8.0",
@@ -5516,7 +5509,7 @@ dependencies = [
  "sp-inherents 2.0.0",
  "sp-keyring 2.0.0",
  "sp-runtime 2.0.0",
- "sp-state-machine 2.0.0",
+ "sp-state-machine 0.8.0",
  "substrate-test-runtime-client 2.0.0",
  "tempfile 3.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio 0.1.22 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -5557,13 +5550,13 @@ dependencies = [
  "linked_hash_set 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "lru 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "quickcheck 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand 0.7.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-hex 2.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "sc-block-builder 2.0.0",
- "sc-client 2.0.0",
+ "rustc-hex 2.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "sc-block-builder 0.8.0",
+ "sc-client 0.8.0",
  "sc-client-api 2.0.0",
  "sc-peerset 2.0.0",
  "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -5589,7 +5582,7 @@ dependencies = [
 
 [[package]]
 name = "sc-network-gossip"
-version = "2.0.0"
+version = "0.8.0"
 dependencies = [
  "futures 0.1.29 (registry+https://github.com/rust-lang/crates.io-index)",
  "futures 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -5604,7 +5597,7 @@ dependencies = [
 
 [[package]]
 name = "sc-network-test"
-version = "2.0.0"
+version = "0.8.0"
 dependencies = [
  "env_logger 0.7.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "futures 0.1.29 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -5614,8 +5607,8 @@ dependencies = [
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand 0.7.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "sc-block-builder 2.0.0",
- "sc-client 2.0.0",
+ "sc-block-builder 0.8.0",
+ "sc-client 0.8.0",
  "sc-client-api 2.0.0",
  "sc-network 0.8.0",
  "sp-blockchain 2.0.0",
@@ -5643,11 +5636,11 @@ dependencies = [
  "hyper-rustls 0.17.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "num_cpus 1.11.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand 0.7.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "sc-client-api 2.0.0",
- "sc-client-db 2.0.0",
+ "sc-client-db 0.8.0",
  "sc-keystore 2.0.0",
  "sc-network 0.8.0",
  "sc-transaction-pool 2.0.0",
@@ -5683,15 +5676,15 @@ dependencies = [
  "jsonrpc-core 14.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "jsonrpc-pubsub 14.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-hex 2.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "sc-client 2.0.0",
+ "rustc-hex 2.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "sc-client 0.8.0",
  "sc-client-api 2.0.0",
- "sc-executor 2.0.0",
+ "sc-executor 0.8.0",
  "sc-keystore 2.0.0",
  "sc-network 0.8.0",
- "sc-rpc-api 2.0.0",
+ "sc-rpc-api 0.8.0",
  "sc-transaction-pool 2.0.0",
  "serde_json 1.0.44 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-api 2.0.0",
@@ -5701,7 +5694,7 @@ dependencies = [
  "sp-rpc 2.0.0",
  "sp-runtime 2.0.0",
  "sp-session 2.0.0",
- "sp-state-machine 2.0.0",
+ "sp-state-machine 0.8.0",
  "sp-transaction-pool 2.0.0",
  "sp-version 2.0.0",
  "substrate-test-runtime-client 2.0.0",
@@ -5710,7 +5703,7 @@ dependencies = [
 
 [[package]]
 name = "sc-rpc-api"
-version = "2.0.0"
+version = "0.8.0"
 dependencies = [
  "derive_more 0.99.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "futures 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -5719,7 +5712,7 @@ dependencies = [
  "jsonrpc-derive 14.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "jsonrpc-pubsub 14.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_json 1.0.44 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -5750,31 +5743,32 @@ dependencies = [
  "sp-core 2.0.0",
  "sp-io 2.0.0",
  "sp-runtime 2.0.0",
- "sp-sandbox 2.0.0",
+ "sp-sandbox 0.8.0",
  "sp-std 2.0.0",
  "substrate-wasm-builder-runner 1.0.4",
 ]
 
 [[package]]
 name = "sc-service"
-version = "2.0.0"
+version = "0.8.0"
 dependencies = [
  "derive_more 0.99.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "exit-future 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "futures 0.1.29 (registry+https://github.com/rust-lang/crates.io-index)",
  "futures 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures-timer 2.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "parity-multiaddr 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "prometheus-endpoint 2.0.0",
+ "prometheus-exporter 0.8.0",
  "sc-chain-spec 2.0.0",
- "sc-client 2.0.0",
+ "sc-client 0.8.0",
  "sc-client-api 2.0.0",
- "sc-client-db 2.0.0",
- "sc-executor 2.0.0",
- "sc-finality-grandpa 2.0.0",
+ "sc-client-db 0.8.0",
+ "sc-executor 0.8.0",
+ "sc-finality-grandpa 0.8.0",
  "sc-keystore 2.0.0",
  "sc-network 0.8.0",
  "sc-offchain 2.0.0",
@@ -5800,9 +5794,8 @@ dependencies = [
  "substrate-test-runtime-client 2.0.0",
  "sysinfo 0.9.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "target_info 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "tokio 0.1.22 (registry+https://github.com/rust-lang/crates.io-index)",
+ "tokio 0.2.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio-executor 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)",
- "tokio-timer 0.2.12 (registry+https://github.com/rust-lang/crates.io-index)",
  "tracing 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -5815,9 +5808,9 @@ dependencies = [
  "futures 0.1.29 (registry+https://github.com/rust-lang/crates.io-index)",
  "futures 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "sc-client 2.0.0",
+ "sc-client 0.8.0",
  "sc-network 0.8.0",
- "sc-service 2.0.0",
+ "sc-service 0.8.0",
  "sp-consensus 0.8.0",
  "sp-core 2.0.0",
  "sp-runtime 2.0.0",
@@ -5828,11 +5821,11 @@ dependencies = [
 
 [[package]]
 name = "sc-state-db"
-version = "2.0.0"
+version = "0.8.0"
 dependencies = [
  "env_logger 0.7.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-core 2.0.0",
 ]
@@ -5881,7 +5874,7 @@ dependencies = [
  "derive_more 0.99.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "futures 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-core 2.0.0",
@@ -5897,7 +5890,7 @@ dependencies = [
  "derive_more 0.99.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "futures 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "sc-client-api 2.0.0",
  "sc-transaction-graph 2.0.0",
@@ -6208,11 +6201,11 @@ name = "sp-api"
 version = "2.0.0"
 dependencies = [
  "hash-db 0.15.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-api-proc-macro 2.0.0",
  "sp-core 2.0.0",
  "sp-runtime 2.0.0",
- "sp-state-machine 2.0.0",
+ "sp-state-machine 0.8.0",
  "sp-std 2.0.0",
  "sp-test-primitives 2.0.0",
  "sp-version 2.0.0",
@@ -6234,13 +6227,13 @@ name = "sp-api-test"
 version = "2.0.0"
 dependencies = [
  "criterion 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustversion 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-api 2.0.0",
  "sp-blockchain 2.0.0",
  "sp-consensus 0.8.0",
  "sp-runtime 2.0.0",
- "sp-state-machine 2.0.0",
+ "sp-state-machine 0.8.0",
  "sp-version 2.0.0",
  "substrate-test-runtime-client 2.0.0",
  "trybuild 1.0.18 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -6250,7 +6243,7 @@ dependencies = [
 name = "sp-application-crypto"
 version = "2.0.0"
 dependencies = [
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-core 2.0.0",
  "sp-io 2.0.0",
@@ -6275,7 +6268,7 @@ dependencies = [
  "criterion 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "integer-sqrt 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "num-traits 0.2.10 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "primitive-types 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand 0.7.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -6287,7 +6280,7 @@ dependencies = [
 name = "sp-authority-discovery"
 version = "2.0.0"
 dependencies = [
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-api 2.0.0",
  "sp-application-crypto 2.0.0",
  "sp-runtime 2.0.0",
@@ -6298,7 +6291,7 @@ dependencies = [
 name = "sp-authorship"
 version = "2.0.0"
 dependencies = [
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-inherents 2.0.0",
  "sp-runtime 2.0.0",
  "sp-std 2.0.0",
@@ -6308,7 +6301,7 @@ dependencies = [
 name = "sp-block-builder"
 version = "2.0.0"
 dependencies = [
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-api 2.0.0",
  "sp-inherents 2.0.0",
  "sp-runtime 2.0.0",
@@ -6322,12 +6315,12 @@ dependencies = [
  "derive_more 0.99.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "lru 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-block-builder 2.0.0",
  "sp-consensus 0.8.0",
  "sp-runtime 2.0.0",
- "sp-state-machine 2.0.0",
+ "sp-state-machine 0.8.0",
 ]
 
 [[package]]
@@ -6339,12 +6332,12 @@ dependencies = [
  "futures-timer 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "libp2p 0.14.0-alpha.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-core 2.0.0",
  "sp-inherents 2.0.0",
  "sp-runtime 2.0.0",
- "sp-state-machine 2.0.0",
+ "sp-state-machine 0.8.0",
  "sp-std 2.0.0",
  "sp-test-primitives 2.0.0",
  "sp-version 2.0.0",
@@ -6354,7 +6347,7 @@ dependencies = [
 name = "sp-consensus-aura"
 version = "0.8.0"
 dependencies = [
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-api 2.0.0",
  "sp-application-crypto 2.0.0",
  "sp-inherents 2.0.0",
@@ -6367,7 +6360,7 @@ dependencies = [
 name = "sp-consensus-babe"
 version = "0.8.0"
 dependencies = [
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "schnorrkel 0.8.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-api 2.0.0",
  "sp-application-crypto 2.0.0",
@@ -6382,7 +6375,7 @@ dependencies = [
 name = "sp-consensus-pow"
 version = "0.8.0"
 dependencies = [
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-api 2.0.0",
  "sp-core 2.0.0",
  "sp-runtime 2.0.0",
@@ -6407,19 +6400,19 @@ dependencies = [
  "libsecp256k1 0.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "num-traits 0.2.10 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "pretty_assertions 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "primitive-types 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand 0.7.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "regex 1.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-hex 2.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-hex 2.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "schnorrkel 0.8.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_json 1.0.44 (registry+https://github.com/rust-lang/crates.io-index)",
  "sha2 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-debug-derive 2.0.0",
- "sp-externalities 2.0.0",
+ "sp-externalities 0.8.0",
  "sp-runtime-interface 2.0.0",
  "sp-serializer 2.0.0",
  "sp-std 2.0.0",
@@ -6443,9 +6436,9 @@ dependencies = [
 
 [[package]]
 name = "sp-externalities"
-version = "2.0.0"
+version = "0.8.0"
 dependencies = [
- "environmental 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "environmental 1.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-std 2.0.0",
  "sp-storage 2.0.0",
 ]
@@ -6454,7 +6447,7 @@ dependencies = [
 name = "sp-finality-grandpa"
 version = "2.0.0"
 dependencies = [
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-api 2.0.0",
  "sp-application-crypto 2.0.0",
@@ -6466,7 +6459,7 @@ dependencies = [
 name = "sp-finality-tracker"
 version = "2.0.0"
 dependencies = [
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-inherents 2.0.0",
  "sp-std 2.0.0",
 ]
@@ -6476,7 +6469,7 @@ name = "sp-inherents"
 version = "2.0.0"
 dependencies = [
  "derive_more 0.99.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-core 2.0.0",
  "sp-std 2.0.0",
@@ -6489,11 +6482,11 @@ dependencies = [
  "hash-db 0.15.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "libsecp256k1 0.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-core 2.0.0",
- "sp-externalities 2.0.0",
+ "sp-externalities 0.8.0",
  "sp-runtime-interface 2.0.0",
- "sp-state-machine 2.0.0",
+ "sp-state-machine 0.8.0",
  "sp-std 2.0.0",
  "sp-trie 2.0.0",
 ]
@@ -6551,7 +6544,7 @@ version = "2.0.0"
 dependencies = [
  "impl-trait-for-tuples 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "paste 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand 0.7.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -6568,16 +6561,15 @@ dependencies = [
 name = "sp-runtime-interface"
 version = "2.0.0"
 dependencies = [
- "environmental 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "primitive-types 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustversion 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-core 2.0.0",
- "sp-externalities 2.0.0",
+ "sp-externalities 0.8.0",
  "sp-io 2.0.0",
  "sp-runtime-interface-proc-macro 2.0.0",
  "sp-runtime-interface-test-wasm 2.0.0",
- "sp-state-machine 2.0.0",
+ "sp-state-machine 0.8.0",
  "sp-std 2.0.0",
  "sp-wasm-interface 2.0.0",
  "static_assertions 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -6599,12 +6591,12 @@ dependencies = [
 name = "sp-runtime-interface-test"
 version = "2.0.0"
 dependencies = [
- "sc-executor 2.0.0",
+ "sc-executor 0.8.0",
  "sp-core 2.0.0",
  "sp-io 2.0.0",
  "sp-runtime-interface 2.0.0",
  "sp-runtime-interface-test-wasm 2.0.0",
- "sp-state-machine 2.0.0",
+ "sp-state-machine 0.8.0",
 ]
 
 [[package]]
@@ -6620,10 +6612,10 @@ dependencies = [
 
 [[package]]
 name = "sp-sandbox"
-version = "2.0.0"
+version = "0.8.0"
 dependencies = [
  "assert_matches 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-core 2.0.0",
  "sp-io 2.0.0",
  "sp-std 2.0.0",
@@ -6652,27 +6644,27 @@ dependencies = [
 name = "sp-staking"
 version = "2.0.0"
 dependencies = [
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-runtime 2.0.0",
  "sp-std 2.0.0",
 ]
 
 [[package]]
 name = "sp-state-machine"
-version = "2.0.0"
+version = "0.8.0"
 dependencies = [
  "hash-db 0.15.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "hex-literal 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "num-traits 0.2.10 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand 0.7.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-core 2.0.0",
- "sp-externalities 2.0.0",
+ "sp-externalities 0.8.0",
  "sp-panic-handler 2.0.0",
  "sp-trie 2.0.0",
- "trie-db 0.18.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "trie-db 0.19.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "trie-root 0.15.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -6694,7 +6686,7 @@ dependencies = [
 name = "sp-test-primitives"
 version = "2.0.0"
 dependencies = [
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-application-crypto 2.0.0",
  "sp-core 2.0.0",
@@ -6706,7 +6698,7 @@ name = "sp-timestamp"
 version = "2.0.0"
 dependencies = [
  "impl-trait-for-tuples 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-api 2.0.0",
  "sp-inherents 2.0.0",
  "sp-runtime 2.0.0",
@@ -6720,7 +6712,7 @@ dependencies = [
  "derive_more 0.99.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "futures 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-api 2.0.0",
  "sp-runtime 2.0.0",
@@ -6733,12 +6725,12 @@ dependencies = [
  "criterion 0.2.11 (registry+https://github.com/rust-lang/crates.io-index)",
  "hash-db 0.15.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "hex-literal 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "memory-db 0.18.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "memory-db 0.18.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-core 2.0.0",
  "sp-std 2.0.0",
- "trie-bench 0.18.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "trie-db 0.18.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "trie-bench 0.19.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "trie-db 0.19.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "trie-root 0.15.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "trie-standardmap 0.15.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -6748,7 +6740,7 @@ name = "sp-version"
 version = "2.0.0"
 dependencies = [
  "impl-serde 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-runtime 2.0.0",
  "sp-std 2.0.0",
@@ -6863,10 +6855,10 @@ dependencies = [
  "node-runtime 2.0.0",
  "pallet-balances 2.0.0",
  "pallet-transaction-payment 2.0.0",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand 0.7.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "rpassword 4.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-hex 2.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-hex 2.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "sc-rpc 2.0.0",
  "sp-core 2.0.0",
  "sp-runtime 2.0.0",
@@ -6898,8 +6890,8 @@ dependencies = [
  "futures 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "jsonrpc-client-transports 14.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "jsonrpc-core 14.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "sc-rpc-api 2.0.0",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "sc-rpc-api 0.8.0",
  "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-storage 2.0.0",
  "tokio 0.1.22 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -6916,8 +6908,8 @@ dependencies = [
  "jsonrpc-core-client 14.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "jsonrpc-derive 14.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "sc-client 2.0.0",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "sc-client 0.8.0",
  "sc-transaction-pool 2.0.0",
  "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-api 2.0.0",
@@ -6934,17 +6926,17 @@ version = "2.0.0"
 dependencies = [
  "futures 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "hash-db 0.15.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "sc-client 2.0.0",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "sc-client 0.8.0",
  "sc-client-api 2.0.0",
- "sc-client-db 2.0.0",
- "sc-executor 2.0.0",
+ "sc-client-db 0.8.0",
+ "sc-executor 0.8.0",
  "sp-blockchain 2.0.0",
  "sp-consensus 0.8.0",
  "sp-core 2.0.0",
  "sp-keyring 2.0.0",
  "sp-runtime 2.0.0",
- "sp-state-machine 2.0.0",
+ "sp-state-machine 0.8.0",
 ]
 
 [[package]]
@@ -6957,12 +6949,12 @@ dependencies = [
  "frame-system 2.0.0",
  "frame-system-rpc-runtime-api 2.0.0",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "memory-db 0.18.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "memory-db 0.18.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "pallet-babe 2.0.0",
  "pallet-timestamp 2.0.0",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "sc-client 2.0.0",
- "sc-executor 2.0.0",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "sc-client 0.8.0",
+ "sc-executor 0.8.0",
  "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
  "sp-api 2.0.0",
  "sp-application-crypto 2.0.0",
@@ -6977,14 +6969,14 @@ dependencies = [
  "sp-runtime 2.0.0",
  "sp-runtime-interface 2.0.0",
  "sp-session 2.0.0",
- "sp-state-machine 2.0.0",
+ "sp-state-machine 0.8.0",
  "sp-std 2.0.0",
  "sp-transaction-pool 2.0.0",
  "sp-trie 2.0.0",
  "sp-version 2.0.0",
  "substrate-test-runtime-client 2.0.0",
  "substrate-wasm-builder-runner 1.0.4",
- "trie-db 0.18.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "trie-db 0.19.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -6992,9 +6984,9 @@ name = "substrate-test-runtime-client"
 version = "2.0.0"
 dependencies = [
  "futures 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "sc-block-builder 2.0.0",
- "sc-client 2.0.0",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "sc-block-builder 0.8.0",
+ "sc-client 0.8.0",
  "sc-client-api 2.0.0",
  "sp-api 2.0.0",
  "sp-blockchain 2.0.0",
@@ -7104,6 +7096,15 @@ name = "target_info"
 version = "0.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "tempdir"
+version = "0.3.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "rand 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "remove_dir_all 0.5.2 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "tempfile"
 version = "3.1.0"
@@ -7259,6 +7260,7 @@ dependencies = [
  "bytes 0.5.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "fnv 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "memchr 2.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "num_cpus 1.11.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "pin-project-lite 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -7523,28 +7525,29 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "trie-bench"
-version = "0.18.0"
+version = "0.19.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "criterion 0.2.11 (registry+https://github.com/rust-lang/crates.io-index)",
  "hash-db 0.15.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "keccak-hasher 0.15.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "memory-db 0.18.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "trie-db 0.18.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "memory-db 0.18.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "trie-db 0.19.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "trie-root 0.15.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "trie-standardmap 0.15.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "trie-db"
-version = "0.18.1"
+version = "0.19.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "hash-db 0.15.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "hashbrown 0.6.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand 0.6.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-hex 2.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "smallvec 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -7618,7 +7621,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "byteorder 1.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "crunchy 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-hex 2.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-hex 2.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "static_assertions 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -8383,7 +8386,7 @@ dependencies = [
 "checksum enumflags2_derive 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)" = "ecf634c5213044b8d54a46dd282cf5dd1f86bb5cb53e92c409cb4680a7fb9894"
 "checksum env_logger 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)" = "aafcde04e90a5226a6443b7aabdb016ba2f8307c847d524724bd9b346dd1a2d3"
 "checksum env_logger 0.7.1 (registry+https://github.com/rust-lang/crates.io-index)" = "44533bbbb3bb3c1fa17d9f2e4e38bbbaf8396ba82193c4cb1b6445d711445d36"
-"checksum environmental 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)" = "34f8467a0284de039e6bd0e25c14519538462ba5beb548bb1f03e645097837a8"
+"checksum environmental 1.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "516aa8d7a71cb00a1c4146f0798549b93d083d4f189b3ced8f3de6b8f11ee6c4"
 "checksum erased-serde 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)" = "3beee4bc16478a1b26f2e80ad819a52d24745e292f521a63c16eea5f74b7eb60"
 "checksum errno 0.2.4 (registry+https://github.com/rust-lang/crates.io-index)" = "c2a071601ed01b988f896ab14b95e67335d1eeb50190932a1320f7fe3cadc84e"
 "checksum errno-dragonfly 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "14ca354e36190500e1e1fb267c647932382b54053c50b14970856c0b00a35067"
@@ -8399,7 +8402,7 @@ dependencies = [
 "checksum fallible-iterator 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "4443176a9f2c162692bd3d352d745ef9413eec5782a80d8fd6f8a1ac692a07f7"
 "checksum fdlimit 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "b1ee15a7050e5580b3712877157068ea713b245b080ff302ae2ca973cfcd9baa"
 "checksum file-per-thread-logger 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)" = "8505b75b31ef7285168dd237c4a7db3c1f3e0927e7d314e670bc98e854272fe9"
-"checksum finality-grandpa 0.10.2 (registry+https://github.com/rust-lang/crates.io-index)" = "4106eb29c7e092f4a6ce6e7632abbbfdf85d94e63035d3790d2d16eeae83d3f4"
+"checksum finality-grandpa 0.10.3 (registry+https://github.com/rust-lang/crates.io-index)" = "2d9ad6bb0e42865b2d79fc9c8a08f22c39127310ed3334f2a1119ca25ed69dfb"
 "checksum fixed-hash 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)" = "72fe7539e2c5692c6989f2f9c0457e42f1e5768f96b85c87d273574670ae459f"
 "checksum fixedbitset 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)" = "86d4de0081402f5e88cdac65c8dcdcc73118c1a7a465e2a05f0da05843a8ea33"
 "checksum flate2 1.0.13 (registry+https://github.com/rust-lang/crates.io-index)" = "6bd6d6f4752952feb71363cffc9ebac9411b75b87c6ab6058c40c8900cf43c0f"
@@ -8538,7 +8541,7 @@ dependencies = [
 "checksum maybe-uninit 2.0.0 (registry+https://github.com/rust-lang/crates.io-index)" = "60302e4db3a61da70c0cb7991976248362f30319e88850c487b9b95bbf059e00"
 "checksum memchr 2.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "88579771288728879b57485cc7d6b07d648c9f0141eb955f8ab7f9d45394468e"
 "checksum memoffset 0.5.3 (registry+https://github.com/rust-lang/crates.io-index)" = "75189eb85871ea5c2e2c15abbdd541185f63b408415e5051f5cac122d8c774b9"
-"checksum memory-db 0.18.0 (registry+https://github.com/rust-lang/crates.io-index)" = "828bdf600636e90c56652689f7c3823ae2072104e4b0b5e83ea984f592f12ab9"
+"checksum memory-db 0.18.1 (registry+https://github.com/rust-lang/crates.io-index)" = "881736a0f68a6fae1b596bb066c5bd16d7b3ed645a4dd8ffaefd02f585abaf71"
 "checksum memory_units 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)" = "71d96e3f3c0b6325d8ccd83c33b28acb183edcb6c67938ba104ec546854b0882"
 "checksum merlin 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)" = "2b0942b357c1b4d0dc43ba724674ec89c3218e6ca2b3e8269e7cb53bcecd2f6e"
 "checksum mime 0.2.6 (registry+https://github.com/rust-lang/crates.io-index)" = "ba626b8a6de5da682e1caa06bdb42a335aee5a84db8e5046a3e8ab17ba0a3ae0"
@@ -8578,7 +8581,7 @@ dependencies = [
 "checksum parity-multiaddr 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)" = "6de20a133b50f5120c6b8284ee88c5017fb167149208b3ee2e95f8719a434dc4"
 "checksum parity-multihash 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)" = "df3a17dc27848fd99e4f87eb0f8c9baba6ede0a6d555400c850ca45254ef4ce3"
 "checksum parity-multihash 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "70a4d7b05e51bff5ae2c29c7b8c3d889985bbd8f4e15b3542fcc1f6f9666d292"
-"checksum parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "f9f9d99dae413590a5f37e43cd99b94d4e62a244160562899126913ea7108673"
+"checksum parity-scale-codec 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)" = "f747c06d9f3b2ad387ac881b9667298c81b1243aa9833f086e05996937c35507"
 "checksum parity-scale-codec-derive 1.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "34e513ff3e406f3ede6796dcdc83d0b32ffb86668cea1ccf7363118abeb00476"
 "checksum parity-send-wrapper 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "aa9777aa91b8ad9dd5aaa04a9b6bcb02c7f1deb952fca5a66034d5e63afc5c6f"
 "checksum parity-util-mem 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)" = "8174d85e62c4d615fddd1ef67966bdc5757528891d0742f15b131ad04667b3f9"
@@ -8665,7 +8668,7 @@ dependencies = [
 "checksum rpassword 4.0.3 (registry+https://github.com/rust-lang/crates.io-index)" = "d59f0e97173c514b9036cd450c195a6483ba81055c6fa0f1bff3ab563f47d44a"
 "checksum rust-argon2 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)" = "4ca4eaef519b494d1f2848fc602d18816fed808a981aedf4f1f00ceb7c9d32cf"
 "checksum rustc-demangle 0.1.16 (registry+https://github.com/rust-lang/crates.io-index)" = "4c691c0e608126e00913e33f0ccf3727d5fc84573623b8d65b2df340b5201783"
-"checksum rustc-hex 2.0.1 (registry+https://github.com/rust-lang/crates.io-index)" = "403bb3a286107a04825a5f82e1270acc1e14028d3d554d7a1e08914549575ab8"
+"checksum rustc-hex 2.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "3e75f6a532d0fd9f7f13144f392b6ad56a32696bfcd9c78f797f16bbb6f072d6"
 "checksum rustc_version 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)" = "c5f5376ea5e30ce23c03eb77cbe4962b988deead10910c372b226388b594c084"
 "checksum rustc_version 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)" = "138e3e0acb6c9fb258b19b67cb8abd63c00679d2851805ea151465464fe9030a"
 "checksum rustls 0.16.0 (registry+https://github.com/rust-lang/crates.io-index)" = "b25a18b1bf7387f0145e7f8324e700805aade3842dd3db2e74e4cdeb4677c09e"
@@ -8731,6 +8734,7 @@ dependencies = [
 "checksum take_mut 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "f764005d11ee5f36500a149ace24e00e3da98b0158b3e2d53a7495660d3f4d60"
 "checksum target-lexicon 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)" = "6f4c118a7a38378f305a9e111fcb2f7f838c0be324bfb31a77ea04f7f6e684b4"
 "checksum target_info 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "c63f48baada5c52e65a29eef93ab4f8982681b67f9e8d29c7b05abcfec2b9ffe"
+"checksum tempdir 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)" = "15f2b5fb00ccdf689e0149d1b1b3c03fead81c2b37735d812fa8bddbbf41b6d8"
 "checksum tempfile 3.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "7a6e24d9338a0a5be79593e2fa15a648add6138caa803e2d5bc782c371732ca9"
 "checksum termcolor 1.0.5 (registry+https://github.com/rust-lang/crates.io-index)" = "96d6098003bde162e4277c70665bd87c326f5a0c3f3fbfb285787fa482d54e6e"
 "checksum test-case 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)" = "a605baa797821796a751f4a959e1206079b24a4b7e1ed302b7d785d81a9276c9"
@@ -8770,8 +8774,8 @@ dependencies = [
 "checksum tracing-attributes 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)" = "a4263b12c3d3c403274493eb805966093b53214124796552d674ca1dd5d27c2b"
 "checksum tracing-core 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)" = "bc913647c520c959b6d21e35ed8fa6984971deca9f0a2fcb8c51207e0c56af1d"
 "checksum traitobject 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "efd1f82c56340fdf16f2a953d7bda4f8fdffba13d93b00844c25572110b26079"
-"checksum trie-bench 0.18.0 (registry+https://github.com/rust-lang/crates.io-index)" = "4d276e600d06806a4ac61e5d6b145a620001e6147151e60a4f1f46a784ec4baa"
-"checksum trie-db 0.18.1 (registry+https://github.com/rust-lang/crates.io-index)" = "191fda5d0106f3ed35a8c6875428b213e15c516e48129cc263dd7ad16e9a665f"
+"checksum trie-bench 0.19.0 (registry+https://github.com/rust-lang/crates.io-index)" = "26fd042d57ee9c987c562811162a78db78b5340ab674ac76056c85dca49b26bc"
+"checksum trie-db 0.19.2 (registry+https://github.com/rust-lang/crates.io-index)" = "a0d747ae5b6f078df7e46477fcc7df66df9eb4f27a031cf4a7c890a8dd03d8e6"
 "checksum trie-root 0.15.2 (registry+https://github.com/rust-lang/crates.io-index)" = "0b779f7c1c8fe9276365d9d5be5c4b5adeacf545117bb3f64c974305789c5c0b"
 "checksum trie-standardmap 0.15.2 (registry+https://github.com/rust-lang/crates.io-index)" = "c3161ba520ab28cd8e6b68e1126f1009f6e335339d1a73b978139011703264c8"
 "checksum try-lock 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "e604eb7b43c06650e854be16a2a03155743d3752dd1c943f6829e26b7a36e382"
diff --git a/bin/node-template/Cargo.toml b/bin/node-template/Cargo.toml
index aaaae647cf564..f956bbb22193a 100644
--- a/bin/node-template/Cargo.toml
+++ b/bin/node-template/Cargo.toml
@@ -11,18 +11,17 @@ path = "src/main.rs"
 
 [dependencies]
 futures = "0.3.1"
-futures01 = { package = "futures", version = "0.1.29" }
 ctrlc = { version = "3.1.3", features = ["termination"] }
 log = "0.4.8"
-tokio = "0.1.22"
+tokio = { version = "0.2", features = ["rt-threaded"] }
 parking_lot = "0.9.0"
 codec = { package = "parity-scale-codec", version = "1.0.0" }
 trie-root = "0.15.2"
 sp-io = { version = "2.0.0", path = "../../primitives/io" }
-sc-cli = { version = "2.0.0", path = "../../client/cli" }
+sc-cli = { version = "0.8.0", path = "../../client/cli" }
 sp-core = { version = "2.0.0", path = "../../primitives/core" }
-sc-executor = { version = "2.0.0", path = "../../client/executor" }
-sc-service = { version = "2.0.0", path = "../../client/service" }
+sc-executor = { version = "0.8", path = "../../client/executor" }
+sc-service = { version = "0.8", path = "../../client/service" }
 sp-inherents = { version = "2.0.0", path = "../../primitives/inherents" }
 sc-transaction-pool = { version = "2.0.0", path = "../../client/transaction-pool" }
 sp-transaction-pool = { version = "2.0.0", path = "../../primitives/transaction-pool" }
@@ -30,12 +29,12 @@ sc-network = { version = "0.8", path = "../../client/network" }
 sc-consensus-aura = { version = "0.8", path = "../../client/consensus/aura" }
 sp-consensus-aura = { version = "0.8", path = "../../primitives/consensus/aura" }
 sp-consensus = { version = "0.8", path = "../../primitives/consensus/common" }
-grandpa = { version = "2.0.0", package = "sc-finality-grandpa", path = "../../client/finality-grandpa" }
+grandpa = { version = "0.8", package = "sc-finality-grandpa", path = "../../client/finality-grandpa" }
 grandpa-primitives = { version = "2.0.0", package = "sp-finality-grandpa", path = "../../primitives/finality-grandpa" }
-sc-client = { version = "2.0.0", path = "../../client/" }
+sc-client = { version = "0.8", path = "../../client/" }
 node-template-runtime = { version = "2.0.0", path = "runtime" }
 sp-runtime = { version = "2.0.0", path = "../../primitives/runtime" }
-sc-basic-authority = { path  = "../../client/basic-authorship" }
+sc-basic-authorship = { path  = "../../client/basic-authorship" }
 
 [build-dependencies]
 vergen = "3.0.4"
diff --git a/bin/node-template/runtime/Cargo.toml b/bin/node-template/runtime/Cargo.toml
index b61ad25f466a4..e048d8baf7bfe 100644
--- a/bin/node-template/runtime/Cargo.toml
+++ b/bin/node-template/runtime/Cargo.toml
@@ -18,7 +18,6 @@ transaction-payment = { version = "2.0.0", default-features = false, package = "
 
 codec = { package = "parity-scale-codec", version = "1.0.0", default-features = false, features = ["derive"] }
 frame-executive = { version = "2.0.0", default-features = false, path = "../../../frame/executive" }
-safe-mix = { version = "1.0.0", default-features = false }
 serde = { version = "1.0.101", optional = true, features = ["derive"] }
 sp-api = { version = "2.0.0", default-features = false, path = "../../../primitives/api" }
 sp-block-builder = { path = "../../../primitives/block-builder", default-features = false}
@@ -47,7 +46,6 @@ std = [
 	"grandpa/std",
 	"indices/std",
 	"randomness-collective-flip/std",
-	"safe-mix/std",
 	"serde",
 	"sp-api/std",
 	"sp-block-builder/std",
diff --git a/bin/node-template/src/cli.rs b/bin/node-template/src/cli.rs
index 16638c4af955d..44764e5c9db41 100644
--- a/bin/node-template/src/cli.rs
+++ b/bin/node-template/src/cli.rs
@@ -1,5 +1,5 @@
 use crate::service;
-use futures::{future::{select, Map}, FutureExt, TryFutureExt, channel::oneshot, compat::Future01CompatExt};
+use futures::{future::{select, Map, Either}, FutureExt, channel::oneshot};
 use std::cell::RefCell;
 use tokio::runtime::Runtime;
 pub use sc_cli::{VersionInfo, IntoExit, error};
@@ -75,36 +75,23 @@ where
 
 	let informant = informant::build(&service);
 
-	let future = select(exit, informant)
-		.map(|_| Ok(()))
-		.compat();
-
-	runtime.executor().spawn(future);
+	let handle = runtime.spawn(select(exit, informant));
 
 	// we eagerly drop the service so that the internal exit future is fired,
 	// but we need to keep holding a reference to the global telemetry guard
 	let _telemetry = service.telemetry();
 
-	let service_res = {
-		let exit = e.into_exit();
-		let service = service
-			.map_err(|err| error::Error::Service(err))
-			.compat();
-		let select = select(service, exit)
-			.map(|_| Ok(()))
-			.compat();
-		runtime.block_on(select)
-	};
+	let exit = e.into_exit();
+	let service_res = runtime.block_on(select(service, exit));
 
 	let _ = exit_send.send(());
 
-	// TODO [andre]: timeout this future #1318
-
-	use futures01::Future;
+	runtime.block_on(handle);
 
-	let _ = runtime.shutdown_on_idle().wait();
-
-	service_res
+	match service_res {
+		Either::Left((res, _)) => res.map_err(error::Error::Service),
+		Either::Right((_, _)) => Ok(())
+	}
 }
 
 // handles ctrl-c
diff --git a/bin/node-template/src/service.rs b/bin/node-template/src/service.rs
index 92db95b5c7d89..ed2299e30f73e 100644
--- a/bin/node-template/src/service.rs
+++ b/bin/node-template/src/service.rs
@@ -11,7 +11,7 @@ use sc_executor::native_executor_instance;
 pub use sc_executor::NativeExecutor;
 use sp_consensus_aura::sr25519::{AuthorityPair as AuraPair};
 use grandpa::{self, FinalityProofProvider as GrandpaFinalityProofProvider};
-use sc_basic_authority;
+use futures::{FutureExt, compat::Future01CompatExt};
 
 // Our native executor instance.
 native_executor_instance!(
@@ -106,7 +106,7 @@ pub fn new_full<C: Send + Default + 'static>(config: Configuration<C, GenesisCon
 		.build()?;
 
 	if participates_in_consensus {
-		let proposer = sc_basic_authority::ProposerFactory {
+		let proposer = sc_basic_authorship::ProposerFactory {
 			client: service.client(),
 			transaction_pool: service.transaction_pool(),
 		};
@@ -163,7 +163,7 @@ pub fn new_full<C: Send + Default + 'static>(config: Configuration<C, GenesisCon
 				service.network(),
 				service.on_exit(),
 				service.spawn_task_handle(),
-			)?);
+			)?.compat().map(drop));
 		},
 		(true, false) => {
 			// start the full GRANDPA voter
@@ -180,7 +180,7 @@ pub fn new_full<C: Send + Default + 'static>(config: Configuration<C, GenesisCon
 
 			// the GRANDPA voter task is considered infallible, i.e.
 			// if it fails we take down the service with it.
-			service.spawn_essential_task(grandpa::run_grandpa_voter(voter_config)?);
+			service.spawn_essential_task(grandpa::run_grandpa_voter(voter_config)?.compat().map(drop));
 		},
 		(_, true) => {
 			grandpa::setup_disabled_grandpa(
diff --git a/bin/node/cli/Cargo.toml b/bin/node/cli/Cargo.toml
index 1f7c90bc3a6c5..c81cf38a9c2ff 100644
--- a/bin/node/cli/Cargo.toml
+++ b/bin/node/cli/Cargo.toml
@@ -25,7 +25,6 @@ crate-type = ["cdylib", "rlib"]
 # third-party dependencies
 codec = { package = "parity-scale-codec", version = "1.0.6" }
 serde = { version = "1.0.102", features = ["derive"] }
-futures01 = { package = "futures", version = "0.1.29" }
 futures = { version = "0.3.1", features = ["compat"] }
 hex-literal = "0.2.1"
 jsonrpc-core = "14.0.3"
@@ -48,20 +47,20 @@ sp-consensus = { version = "0.8", path = "../../../primitives/consensus/common"
 
 # client dependencies
 sc-client-api = { version = "2.0.0", path = "../../../client/api" }
-sc-client = { version = "2.0.0", path = "../../../client/" }
+sc-client = { version = "0.8", path = "../../../client/" }
 sc-chain-spec = { version = "2.0.0", path = "../../../client/chain-spec" }
 sc-transaction-pool = { version = "2.0.0", path = "../../../client/transaction-pool" }
 sp-transaction-pool = { version = "2.0.0", path = "../../../primitives/transaction-pool" }
 sc-network = { version = "0.8", path = "../../../client/network" }
 sc-consensus-babe = { version = "0.8", path = "../../../client/consensus/babe" }
-grandpa = { version = "2.0.0", package = "sc-finality-grandpa", path = "../../../client/finality-grandpa" }
-sc-client-db = { version = "2.0.0", default-features = false, path = "../../../client/db" }
+grandpa = { version = "0.8", package = "sc-finality-grandpa", path = "../../../client/finality-grandpa" }
+sc-client-db = { version = "0.8", default-features = false, path = "../../../client/db" }
 sc-offchain = { version = "2.0.0", path = "../../../client/offchain" }
 sc-rpc = { version = "2.0.0", path = "../../../client/rpc" }
-sc-basic-authority = { version = "2.0.0", path = "../../../client/basic-authorship" }
-sc-service = { version = "2.0.0", default-features = false, path = "../../../client/service" }
+sc-basic-authorship = { version = "0.8", path = "../../../client/basic-authorship" }
+sc-service = { version = "0.8", default-features = false, path = "../../../client/service" }
 sc-telemetry = { version = "2.0.0", path = "../../../client/telemetry" }
-sc-authority-discovery = { version = "2.0.0",  path = "../../../client/authority-discovery" }
+sc-authority-discovery = { version = "0.8",  path = "../../../client/authority-discovery" }
 
 # frame dependencies
 pallet-indices = { version = "2.0.0", path = "../../../frame/indices" }
@@ -81,10 +80,10 @@ node-primitives = { version = "2.0.0", path = "../primitives" }
 node-executor = { version = "2.0.0", path = "../executor" }
 
 # CLI-specific dependencies
-tokio = { version = "0.1.22", optional = true }
-sc-cli = { version = "2.0.0", optional = true, path = "../../../client/cli" }
+tokio = { version = "0.2", features = ["rt-threaded"], optional = true }
+sc-cli = { version = "0.8.0", optional = true, path = "../../../client/cli" }
 ctrlc = { version = "3.1.3", features = ["termination"], optional = true }
-node-transaction-factory = { version = "2.0.0", optional = true, path = "../transaction-factory" }
+node-transaction-factory = { version = "0.8.0", optional = true, path = "../transaction-factory" }
 
 # WASM-specific dependencies
 wasm-bindgen = { version = "0.2.57", optional = true }
@@ -99,7 +98,7 @@ futures = "0.3.1"
 tempfile = "3.1.0"
 
 [build-dependencies]
-sc-cli = { version = "2.0.0", package = "sc-cli", path = "../../../client/cli" }
+sc-cli = { version = "0.8.0", package = "sc-cli", path = "../../../client/cli" }
 build-script-utils = { version = "2.0.0", package = "substrate-build-script-utils", path = "../../../utils/build-script-utils" }
 structopt = "=0.3.7"
 vergen = "3.0.4"
diff --git a/bin/node/cli/src/chain_spec.rs b/bin/node/cli/src/chain_spec.rs
index 26b1f6d2949e3..b8ff948b01b24 100644
--- a/bin/node/cli/src/chain_spec.rs
+++ b/bin/node/cli/src/chain_spec.rs
@@ -21,8 +21,8 @@ use sp_core::{Pair, Public, crypto::UncheckedInto, sr25519};
 use serde::{Serialize, Deserialize};
 use node_runtime::{
 	AuthorityDiscoveryConfig, BabeConfig, BalancesConfig, ContractsConfig, CouncilConfig, DemocracyConfig,
-	GrandpaConfig, ImOnlineConfig, IndicesConfig, SessionConfig, SessionKeys, StakerStatus, StakingConfig, SudoConfig,
-	SystemConfig, TechnicalCommitteeConfig, WASM_BINARY,
+	GrandpaConfig, ImOnlineConfig, IndicesConfig, SessionConfig, SessionKeys, StakerStatus, StakingConfig,
+	SocietyConfig, SudoConfig, SystemConfig, TechnicalCommitteeConfig, WASM_BINARY,
 };
 use node_runtime::Block;
 use node_runtime::constants::currency::*;
@@ -295,6 +295,11 @@ pub fn testnet_genesis(
 		}),
 		pallet_membership_Instance1: Some(Default::default()),
 		pallet_treasury: Some(Default::default()),
+		pallet_society: Some(SocietyConfig {
+			members: endowed_accounts[0..3].to_vec(),
+			pot: 0,
+			max_members: 999,
+		})
 	}
 }
 
diff --git a/bin/node/cli/src/cli.rs b/bin/node/cli/src/cli.rs
index 8fb95bed687bb..dcc5d39dbb7e7 100644
--- a/bin/node/cli/src/cli.rs
+++ b/bin/node/cli/src/cli.rs
@@ -15,7 +15,6 @@
 // along with Substrate.  If not, see <http://www.gnu.org/licenses/>.
 
 pub use sc_cli::VersionInfo;
-use tokio::prelude::Future;
 use tokio::runtime::{Builder as RuntimeBuilder, Runtime};
 use sc_cli::{IntoExit, NoCustom, SharedParams, ImportParams, error};
 use sc_service::{AbstractService, Roles as ServiceRoles, Configuration};
@@ -25,6 +24,7 @@ use sc_cli::{display_role, parse_and_prepare, GetSharedParams, ParseAndPrepare};
 use crate::{service, ChainSpec, load_spec};
 use crate::factory_impl::FactoryState;
 use node_transaction_factory::RuntimeAdapter;
+use futures::{channel::oneshot, future::{select, Either}};
 
 /// Custom subcommands.
 #[derive(Clone, Debug, StructOpt)]
@@ -105,7 +105,10 @@ pub fn run<I, T, E>(args: I, exit: E, version: sc_cli::VersionInfo) -> error::Re
 			info!("Chain specification: {}", config.chain_spec.name());
 			info!("Node name: {}", config.name);
 			info!("Roles: {}", display_role(&config));
-			let runtime = RuntimeBuilder::new().name_prefix("main-tokio-").build()
+			let runtime = RuntimeBuilder::new()
+				.thread_name("main-tokio-")
+				.threaded_scheduler()
+				.build()
 				.map_err(|e| format!("{:?}", e))?;
 			match config.roles {
 				ServiceRoles::LIGHT => run_until_exit(
@@ -135,8 +138,8 @@ pub fn run<I, T, E>(args: I, exit: E, version: sc_cli::VersionInfo) -> error::Re
 				load_spec,
 				&cli_args.shared_params,
 				&version,
+				None,
 			)?;
-
 			sc_cli::fill_import_params(&mut config, &cli_args.import_params, ServiceRoles::FULL)?;
 
 			match ChainSpec::from(config.chain_spec.id()) {
@@ -172,37 +175,25 @@ where
 	T: AbstractService,
 	E: IntoExit,
 {
-	use futures::{FutureExt, TryFutureExt, channel::oneshot, future::select, compat::Future01CompatExt};
-
 	let (exit_send, exit) = oneshot::channel();
 
 	let informant = sc_cli::informant::build(&service);
 
-	let future = select(informant, exit)
-		.map(|_| Ok(()))
-		.compat();
-
-	runtime.executor().spawn(future);
+	let handle = runtime.spawn(select(exit, informant));
 
 	// we eagerly drop the service so that the internal exit future is fired,
 	// but we need to keep holding a reference to the global telemetry guard
 	let _telemetry = service.telemetry();
 
-	let service_res = {
-		let exit = e.into_exit();
-		let service = service
-			.map_err(|err| error::Error::Service(err))
-			.compat();
-		let select = select(service, exit)
-			.map(|_| Ok(()))
-			.compat();
-		runtime.block_on(select)
-	};
+	let exit = e.into_exit();
+	let service_res = runtime.block_on(select(service, exit));
 
 	let _ = exit_send.send(());
 
-	// TODO [andre]: timeout this future #1318
-	let _ = runtime.shutdown_on_idle().wait();
+	runtime.block_on(handle);
 
-	service_res
+	match service_res {
+		Either::Left((res, _)) => res.map_err(error::Error::Service),
+		Either::Right((_, _)) => Ok(())
+	}
 }
diff --git a/bin/node/cli/src/service.rs b/bin/node/cli/src/service.rs
index 97ecb7a38f2f7..b12dfcdc515f5 100644
--- a/bin/node/cli/src/service.rs
+++ b/bin/node/cli/src/service.rs
@@ -113,8 +113,8 @@ macro_rules! new_full_start {
 macro_rules! new_full {
 	($config:expr, $with_startup_data: expr) => {{
 		use futures::{
-			stream::StreamExt,
-			future::{FutureExt, TryFutureExt},
+			prelude::*,
+			compat::Future01CompatExt
 		};
 		use sc_network::Event;
 
@@ -151,7 +151,7 @@ macro_rules! new_full {
 		($with_startup_data)(&block_import, &babe_link);
 
 		if participates_in_consensus {
-			let proposer = sc_basic_authority::ProposerFactory {
+			let proposer = sc_basic_authorship::ProposerFactory {
 				client: service.client(),
 				transaction_pool: service.transaction_pool(),
 			};
@@ -191,9 +191,8 @@ macro_rules! new_full {
 				service.keystore(),
 				dht_event_stream,
 			);
-			let future01_authority_discovery = authority_discovery.map(|x| Ok(x)).compat();
 
-			service.spawn_task(future01_authority_discovery);
+			service.spawn_task(authority_discovery);
 		}
 
 		// if the node isn't actively participating in consensus then it doesn't
@@ -223,7 +222,7 @@ macro_rules! new_full {
 					service.network(),
 					service.on_exit(),
 					service.spawn_task_handle(),
-				)?);
+				)?.compat().map(drop));
 			},
 			(true, false) => {
 				// start the full GRANDPA voter
@@ -239,7 +238,9 @@ macro_rules! new_full {
 				};
 				// the GRANDPA voter task is considered infallible, i.e.
 				// if it fails we take down the service with it.
-				service.spawn_essential_task(grandpa::run_grandpa_voter(grandpa_config)?);
+				service.spawn_essential_task(
+					grandpa::run_grandpa_voter(grandpa_config)?.compat().map(drop)
+				);
 			},
 			(_, true) => {
 				grandpa::setup_disabled_grandpa(
@@ -508,7 +509,7 @@ mod tests {
 
 				let parent_id = BlockId::number(service.client().chain_info().best_number);
 				let parent_header = service.client().header(&parent_id).unwrap().unwrap();
-				let mut proposer_factory = sc_basic_authority::ProposerFactory {
+				let mut proposer_factory = sc_basic_authorship::ProposerFactory {
 					client: service.client(),
 					transaction_pool: service.transaction_pool(),
 				};
@@ -534,13 +535,15 @@ mod tests {
 
 				digest.push(<DigestItem as CompatibleDigestItem>::babe_pre_digest(babe_pre_digest));
 
-				let mut proposer = proposer_factory.init(&parent_header).unwrap();
-				let new_block = futures::executor::block_on(proposer.propose(
-					inherent_data,
-					digest,
-					std::time::Duration::from_secs(1),
-					RecordProof::Yes,
-				)).expect("Error making test block").block;
+				let new_block = futures::executor::block_on(async move {
+					let proposer = proposer_factory.init(&parent_header).await;
+					proposer.unwrap().propose(
+						inherent_data,
+						digest,
+						std::time::Duration::from_secs(1),
+						RecordProof::Yes,
+					).await
+				}).expect("Error making test block").block;
 
 				let (new_header, new_body) = new_block.deconstruct();
 				let pre_hash = new_header.hash();
diff --git a/bin/node/executor/Cargo.toml b/bin/node/executor/Cargo.toml
index 3aa7ad780a8db..6e624e09d28dd 100644
--- a/bin/node/executor/Cargo.toml
+++ b/bin/node/executor/Cargo.toml
@@ -9,10 +9,10 @@ edition = "2018"
 codec = { package = "parity-scale-codec", version = "1.0.0" }
 node-primitives = { version = "2.0.0", path = "../primitives" }
 node-runtime = { version = "2.0.0", path = "../runtime" }
-sc-executor = { version = "2.0.0", path = "../../../client/executor" }
+sc-executor = { version = "0.8", path = "../../../client/executor" }
 sp-core = { version = "2.0.0", path = "../../../primitives/core" }
 sp-io = { version = "2.0.0", path = "../../../primitives/io" }
-sp-state-machine = { version = "2.0.0", path = "../../../primitives/state-machine" }
+sp-state-machine = { version = "0.8", path = "../../../primitives/state-machine" }
 sp-trie = { version = "2.0.0", path = "../../../primitives/trie" }
 trie-root = "0.15.2"
 
diff --git a/bin/node/rpc/Cargo.toml b/bin/node/rpc/Cargo.toml
index 8c96542a8e6bd..174b2875166c2 100644
--- a/bin/node/rpc/Cargo.toml
+++ b/bin/node/rpc/Cargo.toml
@@ -5,13 +5,13 @@ authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2018"
 
 [dependencies]
-sc-client = { version = "2.0.0", path = "../../../client/" }
+sc-client = { version = "0.8", path = "../../../client/" }
 jsonrpc-core = "14.0.3"
 node-primitives = { version = "2.0.0", path = "../primitives" }
 node-runtime = { version = "2.0.0", path = "../runtime" }
 sp-runtime = { version = "2.0.0", path = "../../../primitives/runtime" }
 sp-api = { version = "2.0.0", path = "../../../primitives/api" }
-pallet-contracts-rpc = { version = "2.0.0", path = "../../../frame/contracts/rpc/" }
+pallet-contracts-rpc = { version = "0.8.0", path = "../../../frame/contracts/rpc/" }
 pallet-transaction-payment-rpc = { version = "2.0.0", path = "../../../frame/transaction-payment/rpc/" }
 substrate-frame-rpc-system = { version = "2.0.0", path = "../../../utils/frame/rpc/system" }
 sp-transaction-pool = { version = "2.0.0", path = "../../../primitives/transaction-pool" }
diff --git a/bin/node/runtime/Cargo.toml b/bin/node/runtime/Cargo.toml
index a8f26d13cba40..27b1e9382f933 100644
--- a/bin/node/runtime/Cargo.toml
+++ b/bin/node/runtime/Cargo.toml
@@ -9,7 +9,6 @@ build = "build.rs"
 # third-party dependencies
 codec = { package = "parity-scale-codec", version = "1.0.6", default-features = false, features = ["derive"] }
 integer-sqrt = { version = "0.1.2" }
-safe-mix = { version = "1.0", default-features = false }
 rustc-hex = { version = "2.0", optional = true }
 serde = { version = "1.0.102", optional = true }
 
@@ -41,21 +40,23 @@ pallet-babe = { version = "2.0.0", default-features = false, path = "../../../fr
 pallet-balances = { version = "2.0.0", default-features = false, path = "../../../frame/balances" }
 pallet-collective = { version = "2.0.0", default-features = false, path = "../../../frame/collective" }
 pallet-contracts = { version = "2.0.0", default-features = false, path = "../../../frame/contracts" }
-pallet-contracts-rpc-runtime-api = { version = "2.0.0", default-features = false, path = "../../../frame/contracts/rpc/runtime-api/" }
+pallet-contracts-rpc-runtime-api = { version = "0.8.0", default-features = false, path = "../../../frame/contracts/rpc/runtime-api/" }
 pallet-democracy = { version = "2.0.0", default-features = false, path = "../../../frame/democracy" }
 pallet-elections-phragmen = { version = "2.0.0", default-features = false, path = "../../../frame/elections-phragmen" }
 pallet-finality-tracker = { version = "2.0.0", default-features = false, path = "../../../frame/finality-tracker" }
 pallet-grandpa = { version = "2.0.0", default-features = false, path = "../../../frame/grandpa" }
 pallet-im-online = { version = "2.0.0", default-features = false, path = "../../../frame/im-online" }
 pallet-indices = { version = "2.0.0", default-features = false, path = "../../../frame/indices" }
+pallet-identity = { version = "2.0.0", default-features = false, path = "../../../frame/identity" }
 pallet-membership = { version = "2.0.0", default-features = false, path = "../../../frame/membership" }
-pallet-nicks = { version = "2.0.0", default-features = false, path = "../../../frame/nicks" }
 pallet-offences = { version = "2.0.0", default-features = false, path = "../../../frame/offences" }
 pallet-randomness-collective-flip = { version = "2.0.0", default-features = false, path = "../../../frame/randomness-collective-flip" }
+pallet-recovery = { version = "2.0.0", default-features = false, path = "../../../frame/recovery" }
 pallet-session = { version = "2.0.0", features = ["historical"], path = "../../../frame/session", default-features = false }
 pallet-staking = { version = "2.0.0", features = ["migrate"], path = "../../../frame/staking", default-features = false }
 pallet-staking-reward-curve = { version = "2.0.0",  path = "../../../frame/staking/reward-curve" }
 pallet-sudo = { version = "2.0.0", default-features = false, path = "../../../frame/sudo" }
+pallet-society = { version = "2.0.0", default-features = false, path = "../../../frame/society" }
 pallet-timestamp = { version = "2.0.0", default-features = false, path = "../../../frame/timestamp" }
 pallet-treasury = { version = "2.0.0", default-features = false, path = "../../../frame/treasury" }
 pallet-utility = { version = "2.0.0", default-features = false, path = "../../../frame/utility" }
@@ -91,7 +92,7 @@ std = [
 	"pallet-indices/std",
 	"sp-inherents/std",
 	"pallet-membership/std",
-	"pallet-nicks/std",
+	"pallet-identity/std",
 	"node-primitives/std",
 	"sp-offchain/std",
 	"pallet-offences/std",
@@ -99,7 +100,6 @@ std = [
 	"pallet-randomness-collective-flip/std",
 	"sp-std/std",
 	"rustc-hex",
-	"safe-mix/std",
 	"serde",
 	"pallet-session/std",
 	"sp-api/std",
@@ -119,4 +119,6 @@ std = [
 	"sp-transaction-pool/std",
 	"pallet-utility/std",
 	"sp-version/std",
+	"pallet-society/std",
+	"pallet-recovery/std",
 ]
diff --git a/bin/node/runtime/src/lib.rs b/bin/node/runtime/src/lib.rs
index 4266ad7459e65..d769be7b505d5 100644
--- a/bin/node/runtime/src/lib.rs
+++ b/bin/node/runtime/src/lib.rs
@@ -80,8 +80,8 @@ pub const VERSION: RuntimeVersion = RuntimeVersion {
 	// and set impl_version to equal spec_version. If only runtime
 	// implementation changes and behavior does not, then leave spec_version as
 	// is and increment impl_version.
-	spec_version: 203,
-	impl_version: 203,
+	spec_version: 204,
+	impl_version: 204,
 	apis: RUNTIME_API_VERSIONS,
 };
 
@@ -174,7 +174,7 @@ parameter_types! {
 impl pallet_balances::Trait for Runtime {
 	type Balance = Balance;
 	type OnFreeBalanceZero = ((Staking, Contracts), Session);
-	type OnReapAccount = System;
+	type OnReapAccount = (System, Recovery);
 	type OnNewAccount = Indices;
 	type Event = Event;
 	type DustRemoval = ();
@@ -488,19 +488,22 @@ impl pallet_finality_tracker::Trait for Runtime {
 }
 
 parameter_types! {
-	pub const ReservationFee: Balance = 1 * DOLLARS;
-	pub const MinLength: usize = 3;
-	pub const MaxLength: usize = 16;
+	pub const BasicDeposit: Balance = 10 * DOLLARS;       // 258 bytes on-chain
+	pub const FieldDeposit: Balance = 250 * CENTS;        // 66 bytes on-chain
+	pub const SubAccountDeposit: Balance = 2 * DOLLARS;   // 53 bytes on-chain
+	pub const MaximumSubAccounts: u32 = 100;
 }
 
-impl pallet_nicks::Trait for Runtime {
+impl pallet_identity::Trait for Runtime {
 	type Event = Event;
 	type Currency = Balances;
-	type ReservationFee = ReservationFee;
 	type Slashed = Treasury;
-	type ForceOrigin = pallet_collective::EnsureMember<AccountId, CouncilCollective>;
-	type MinLength = MinLength;
-	type MaxLength = MaxLength;
+	type BasicDeposit = BasicDeposit;
+	type FieldDeposit = FieldDeposit;
+	type SubAccountDeposit = SubAccountDeposit;
+	type MaximumSubAccounts = MaximumSubAccounts;
+	type RegistrarOrigin = pallet_collective::EnsureProportionMoreThan<_1, _2, AccountId, CouncilCollective>;
+	type ForceOrigin = pallet_collective::EnsureProportionMoreThan<_1, _2, AccountId, CouncilCollective>;
 }
 
 impl frame_system::offchain::CreateTransaction<Runtime, UncheckedExtrinsic> for Runtime {
@@ -543,6 +546,49 @@ impl frame_system::offchain::CreateTransaction<Runtime, UncheckedExtrinsic> for
 	}
 }
 
+parameter_types! {
+	pub const ConfigDepositBase: Balance = 5 * DOLLARS;
+	pub const FriendDepositFactor: Balance = 50 * CENTS;
+	pub const MaxFriends: u16 = 9;
+	pub const RecoveryDeposit: Balance = 5 * DOLLARS;
+}
+
+impl pallet_recovery::Trait for Runtime {
+	type Event = Event;
+	type Call = Call;
+	type Currency = Balances;
+	type ConfigDepositBase = ConfigDepositBase;
+	type FriendDepositFactor = FriendDepositFactor;
+	type MaxFriends = MaxFriends;
+	type RecoveryDeposit = RecoveryDeposit;
+}
+
+parameter_types! {
+	pub const CandidateDeposit: Balance = 10 * DOLLARS;
+	pub const WrongSideDeduction: Balance = 2 * DOLLARS;
+	pub const MaxStrikes: u32 = 10;
+	pub const RotationPeriod: BlockNumber = 80 * HOURS;
+	pub const PeriodSpend: Balance = 500 * DOLLARS;
+	pub const MaxLockDuration: BlockNumber = 36 * 30 * DAYS;
+	pub const ChallengePeriod: BlockNumber = 7 * DAYS;
+}
+
+impl pallet_society::Trait for Runtime {
+	type Event = Event;
+	type Currency = Balances;
+	type Randomness = RandomnessCollectiveFlip;
+	type CandidateDeposit = CandidateDeposit;
+	type WrongSideDeduction = WrongSideDeduction;
+	type MaxStrikes = MaxStrikes;
+	type PeriodSpend = PeriodSpend;
+	type MembershipChanged = ();
+	type RotationPeriod = RotationPeriod;
+	type MaxLockDuration = MaxLockDuration;
+	type FounderSetOrigin = pallet_collective::EnsureProportionMoreThan<_1, _2, AccountId, CouncilCollective>;
+	type SuspensionJudgementOrigin = pallet_society::EnsureFounder<Runtime>;
+	type ChallengePeriod = ChallengePeriod;
+}
+
 construct_runtime!(
 	pub enum Runtime where
 		Block = Block,
@@ -573,7 +619,9 @@ construct_runtime!(
 		AuthorityDiscovery: pallet_authority_discovery::{Module, Call, Config},
 		Offences: pallet_offences::{Module, Call, Storage, Event},
 		RandomnessCollectiveFlip: pallet_randomness_collective_flip::{Module, Call, Storage},
-		Nicks: pallet_nicks::{Module, Call, Storage, Event<T>},
+		Identity: pallet_identity::{Module, Call, Storage, Event<T>},
+		Society: pallet_society::{Module, Call, Storage, Event<T>, Config<T>},
+		Recovery: pallet_recovery::{Module, Call, Storage, Event<T>},
 	}
 );
 
diff --git a/bin/node/testing/Cargo.toml b/bin/node/testing/Cargo.toml
index 4449c7bd22d47..37e85452d5425 100644
--- a/bin/node/testing/Cargo.toml
+++ b/bin/node/testing/Cargo.toml
@@ -7,7 +7,7 @@ edition = "2018"
 
 [dependencies]
 pallet-balances = { version = "2.0.0", path = "../../../frame/balances" }
-sc-client = { version = "2.0.0", path = "../../../client/" }
+sc-client = { version = "0.8", path = "../../../client/" }
 codec = { package = "parity-scale-codec", version = "1.0.0" }
 pallet-contracts = { version = "2.0.0", path = "../../../frame/contracts" }
 pallet-grandpa = { version = "2.0.0", path = "../../../frame/grandpa" }
@@ -20,9 +20,10 @@ sp-core = { version = "2.0.0", path = "../../../primitives/core" }
 sp-io = { version = "2.0.0", path = "../../../primitives/io" }
 frame-support = { version = "2.0.0", path = "../../../frame/support" }
 pallet-session = { version = "2.0.0", path = "../../../frame/session" }
+pallet-society = { version = "2.0.0", path = "../../../frame/society" }
 sp-runtime = { version = "2.0.0", path = "../../../primitives/runtime" }
 pallet-staking = { version = "2.0.0", path = "../../../frame/staking" }
-sc-executor = { version = "2.0.0", path = "../../../client/executor" }
+sc-executor = { version = "0.8", path = "../../../client/executor" }
 frame-system = { version = "2.0.0", path = "../../../frame/system" }
 substrate-test-client = { version = "2.0.0", path = "../../../test-utils/client" }
 pallet-timestamp = { version = "2.0.0", path = "../../../frame/timestamp" }
diff --git a/bin/node/testing/src/genesis.rs b/bin/node/testing/src/genesis.rs
index 44dd79a7f438a..183515f27274b 100644
--- a/bin/node/testing/src/genesis.rs
+++ b/bin/node/testing/src/genesis.rs
@@ -20,7 +20,7 @@ use crate::keyring::*;
 use sp_keyring::{Ed25519Keyring, Sr25519Keyring};
 use node_runtime::{
 	GenesisConfig, BalancesConfig, SessionConfig, StakingConfig, SystemConfig,
-	GrandpaConfig, IndicesConfig, ContractsConfig, WASM_BINARY,
+	GrandpaConfig, IndicesConfig, ContractsConfig, SocietyConfig, WASM_BINARY,
 };
 use node_runtime::constants::currency::*;
 use sp_core::ChangesTrieConfiguration;
@@ -96,5 +96,10 @@ pub fn config(support_changes_trie: bool, code: Option<&[u8]>) -> GenesisConfig
 		pallet_membership_Instance1: Some(Default::default()),
 		pallet_sudo: Some(Default::default()),
 		pallet_treasury: Some(Default::default()),
+		pallet_society: Some(SocietyConfig {
+			members: vec![alice(), bob()],
+			pot: 0,
+			max_members: 999,
+		}),
 	}
 }
diff --git a/bin/node/transaction-factory/Cargo.toml b/bin/node/transaction-factory/Cargo.toml
index 8b10e10f41f81..f32a3c23e0e01 100644
--- a/bin/node/transaction-factory/Cargo.toml
+++ b/bin/node/transaction-factory/Cargo.toml
@@ -1,19 +1,19 @@
 [package]
 name = "node-transaction-factory"
-version = "2.0.0"
+version = "0.8.0"
 authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2018"
 
 [dependencies]
 sp-block-builder = { version = "2.0.0", path = "../../../primitives/block-builder" }
-sc-cli = { version = "2.0.0", path = "../../../client/cli" }
+sc-cli = { version = "0.8.0", path = "../../../client/cli" }
 sc-client-api = { version = "2.0.0", path = "../../../client/api" }
-sc-client = { version = "2.0.0", path = "../../../client" }
+sc-client = { version = "0.8", path = "../../../client" }
 codec = { package = "parity-scale-codec", version = "1.0.0", features = ["derive"] }
 sp-consensus = { version = "0.8", path = "../../../primitives/consensus/common" }
 log = "0.4.8"
 sp-core = { version = "2.0.0", path = "../../../primitives/core" }
 sp-api = { version = "2.0.0", path = "../../../primitives/api" }
 sp-runtime = { version = "2.0.0", path = "../../../primitives/runtime" }
-sc-service = { version = "2.0.0", path = "../../../client/service" }
+sc-service = { version = "0.8", path = "../../../client/service" }
 sp-blockchain = { version = "2.0.0", path = "../../../primitives/blockchain" }
diff --git a/client/Cargo.toml b/client/Cargo.toml
index eaddd9f3dcfe6..7413fc23f9e2c 100644
--- a/client/Cargo.toml
+++ b/client/Cargo.toml
@@ -1,17 +1,17 @@
 [package]
 name = "sc-client"
-version = "2.0.0"
+version = "0.8.0"
 authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2018"
 
 [dependencies]
-sc-block-builder = { version = "2.0.0", path = "block-builder" }
+sc-block-builder = { version = "0.8", path = "block-builder" }
 sc-client-api = { version = "2.0.0", path = "api" }
 codec = { package = "parity-scale-codec", version = "1.0.0", features = ["derive"] }
 sp-consensus = { version = "0.8", path = "../primitives/consensus/common" }
 derive_more = { version = "0.99.2" }
-sc-executor = { version = "2.0.0", path = "executor" }
-sp-externalities = { version = "2.0.0", path = "../primitives/externalities" }
+sc-executor = { version = "0.8", path = "executor" }
+sp-externalities = { version = "0.8.0", path = "../primitives/externalities" }
 fnv = { version = "1.0.6" }
 futures = { version = "0.3.1", features = ["compat"] }
 hash-db = { version = "0.15.2" }
@@ -27,7 +27,7 @@ sp-version = { version = "2.0.0", path = "../primitives/version" }
 sp-api = { version = "2.0.0", path = "../primitives/api" }
 sp-runtime = { version = "2.0.0", path = "../primitives/runtime" }
 sp-blockchain = { version = "2.0.0", path = "../primitives/blockchain" }
-sp-state-machine = { version = "2.0.0", path = "../primitives/state-machine" }
+sp-state-machine = { version = "0.8", path = "../primitives/state-machine" }
 sc-telemetry = { version = "2.0.0", path = "telemetry" }
 sp-trie = { version = "2.0.0", path = "../primitives/trie" }
 tracing = "0.1.10"
diff --git a/client/api/Cargo.toml b/client/api/Cargo.toml
index 36360a6fb8d20..651ee1434f7fc 100644
--- a/client/api/Cargo.toml
+++ b/client/api/Cargo.toml
@@ -8,8 +8,8 @@ edition = "2018"
 codec = { package = "parity-scale-codec", version = "1.0.0", default-features = false, features = ["derive"] }
 sp-consensus = { version = "0.8", path = "../../primitives/consensus/common" }
 derive_more = { version = "0.99.2" }
-sc-executor = { version = "2.0.0", path = "../executor" }
-sp-externalities = { version = "2.0.0", path = "../../primitives/externalities" }
+sc-executor = { version = "0.8", path = "../executor" }
+sp-externalities = { version = "0.8.0", path = "../../primitives/externalities" }
 fnv = { version = "1.0.6" }
 futures = { version = "0.3.1" }
 hash-db = { version = "0.15.2", default-features = false }
@@ -25,7 +25,7 @@ sp-std = { version = "2.0.0", default-features = false, path = "../../primitives
 sp-version = { version = "2.0.0", default-features = false, path = "../../primitives/version" }
 sp-api = { version = "2.0.0", path = "../../primitives/api" }
 sp-runtime = { version = "2.0.0", default-features = false, path = "../../primitives/runtime" }
-sp-state-machine = { version = "2.0.0", path = "../../primitives/state-machine" }
+sp-state-machine = { version = "0.8", path = "../../primitives/state-machine" }
 sc-telemetry = { version = "2.0.0", path = "../telemetry" }
 sp-trie = { version = "2.0.0", path = "../../primitives/trie" }
 sp-transaction-pool = { version = "2.0.0", path = "../../primitives/transaction-pool" }
diff --git a/client/api/src/backend.rs b/client/api/src/backend.rs
index 292031a4cb9de..a389af5671b32 100644
--- a/client/api/src/backend.rs
+++ b/client/api/src/backend.rs
@@ -18,11 +18,14 @@
 
 use std::sync::Arc;
 use std::collections::HashMap;
-use sp_core::ChangesTrieConfiguration;
+use sp_core::ChangesTrieConfigurationRange;
 use sp_core::offchain::OffchainStorage;
 use sp_runtime::{generic::BlockId, Justification, Storage};
 use sp_runtime::traits::{Block as BlockT, NumberFor, HasherFor};
-use sp_state_machine::{ChangesTrieStorage as StateChangesTrieStorage, ChangesTrieTransaction};
+use sp_state_machine::{
+	ChangesTrieState, ChangesTrieStorage as StateChangesTrieStorage, ChangesTrieTransaction,
+	StorageCollection, ChildStorageCollection,
+};
 use crate::{
 	blockchain::{
 		Backend as BlockchainBackend, well_known_cache_keys
@@ -45,12 +48,6 @@ pub type TransactionForSB<B, Block> = <B as StateBackend<HasherFor<Block>>>::Tra
 /// Extracts the transaction for the given backend.
 pub type TransactionFor<B, Block> = TransactionForSB<StateBackendFor<B, Block>, Block>;
 
-/// In memory array of storage values.
-pub type StorageCollection = Vec<(Vec<u8>, Option<Vec<u8>>)>;
-
-/// In memory arrays of storage values for multiple child tries.
-pub type ChildStorageCollection = Vec<(Vec<u8>, StorageCollection)>;
-
 /// Import operation summary.
 ///
 /// Contains information about the block that just got imported,
@@ -248,8 +245,6 @@ pub trait Backend<Block: BlockT>: AuxStore + Send + Sync {
 	type Blockchain: BlockchainBackend<Block>;
 	/// Associated state backend type.
 	type State: StateBackend<HasherFor<Block>> + Send;
-	/// Changes trie storage.
-	type ChangesTrieStorage: PrunableStateChangesTrieStorage<Block>;
 	/// Offchain workers local storage.
 	type OffchainStorage: OffchainStorage;
 
@@ -284,7 +279,7 @@ pub trait Backend<Block: BlockT>: AuxStore + Send + Sync {
 	fn usage_info(&self) -> Option<UsageInfo>;
 
 	/// Returns reference to changes trie storage.
-	fn changes_trie_storage(&self) -> Option<&Self::ChangesTrieStorage>;
+	fn changes_trie_storage(&self) -> Option<&dyn PrunableStateChangesTrieStorage<Block>>;
 
 	/// Returns a handle to offchain storage.
 	fn offchain_storage(&self) -> Option<Self::OffchainStorage>;
@@ -342,12 +337,16 @@ pub trait Backend<Block: BlockT>: AuxStore + Send + Sync {
 pub trait PrunableStateChangesTrieStorage<Block: BlockT>:
 	StateChangesTrieStorage<HasherFor<Block>, NumberFor<Block>>
 {
-	/// Get number block of oldest, non-pruned changes trie.
-	fn oldest_changes_trie_block(
-		&self,
-		config: &ChangesTrieConfiguration,
-		best_finalized: NumberFor<Block>,
-	) -> NumberFor<Block>;
+	/// Get reference to StateChangesTrieStorage.
+	fn storage(&self) -> &dyn StateChangesTrieStorage<HasherFor<Block>, NumberFor<Block>>;
+	/// Get configuration at given block.
+	fn configuration_at(&self, at: &BlockId<Block>) -> sp_blockchain::Result<
+		ChangesTrieConfigurationRange<NumberFor<Block>, Block::Hash>
+	>;
+	/// Get end block (inclusive) of oldest pruned max-level (or skewed) digest trie blocks range.
+	/// It is guaranteed that we have no any changes tries before (and including) this block.
+	/// It is guaranteed that all existing changes tries after this block are not yet pruned (if created).
+	fn oldest_pruned_digest_range_end(&self) -> NumberFor<Block>;
 }
 
 /// Mark for all Backend implementations, that are making use of state data, stored locally.
@@ -364,3 +363,20 @@ pub trait RemoteBackend<Block: BlockT>: Backend<Block> {
 	/// locally, or prepares request to fetch that data from remote node.
 	fn remote_blockchain(&self) -> Arc<dyn RemoteBlockchain<Block>>;
 }
+
+/// Return changes tries state at given block.
+pub fn changes_tries_state_at_block<'a, Block: BlockT>(
+	block: &BlockId<Block>,
+	maybe_storage: Option<&'a dyn PrunableStateChangesTrieStorage<Block>>,
+) -> sp_blockchain::Result<Option<ChangesTrieState<'a, HasherFor<Block>, NumberFor<Block>>>> {
+	let storage = match maybe_storage {
+		Some(storage) => storage,
+		None => return Ok(None),
+	};
+
+	let config_range = storage.configuration_at(block)?;
+	match config_range.config {
+		Some(config) => Ok(Some(ChangesTrieState::new(config, config_range.zero.0, storage.storage()))),
+		None => Ok(None),
+	}
+}
diff --git a/client/api/src/light.rs b/client/api/src/light.rs
index fb3aeeab7c733..fc9b6dc6fd28c 100644
--- a/client/api/src/light.rs
+++ b/client/api/src/light.rs
@@ -26,7 +26,7 @@ use sp_runtime::{
     },
     generic::BlockId
 };
-use sp_core::ChangesTrieConfiguration;
+use sp_core::ChangesTrieConfigurationRange;
 use sp_state_machine::StorageProof;
 use sp_blockchain::{
 	HeaderMetadata, well_known_cache_keys, HeaderBackend, Cache as BlockchainCache,
@@ -96,8 +96,8 @@ pub struct RemoteReadChildRequest<Header: HeaderT> {
 /// Remote key changes read request.
 #[derive(Clone, Debug, PartialEq, Eq)]
 pub struct RemoteChangesRequest<Header: HeaderT> {
-	/// Changes trie configuration.
-	pub changes_trie_config: ChangesTrieConfiguration,
+	/// All changes trie configurations that are valid within [first_block; last_block].
+	pub changes_trie_configs: Vec<ChangesTrieConfigurationRange<Header::Number, Header::Hash>>,
 	/// Query changes from range of blocks, starting (and including) with this hash...
 	pub first_block: (Header::Number, Header::Hash),
 	/// ...ending (and including) with this hash. Should come after first_block and
diff --git a/client/authority-discovery/Cargo.toml b/client/authority-discovery/Cargo.toml
index 767be822d7858..7381e5add19a1 100644
--- a/client/authority-discovery/Cargo.toml
+++ b/client/authority-discovery/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "sc-authority-discovery"
-version = "2.0.0"
+version = "0.8.0"
 authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2018"
 build = "build.rs"
diff --git a/client/authority-discovery/src/tests.rs b/client/authority-discovery/src/tests.rs
index 07e1c943be638..77ed6a1d948e2 100644
--- a/client/authority-discovery/src/tests.rs
+++ b/client/authority-discovery/src/tests.rs
@@ -212,12 +212,10 @@ impl ApiExt<Block> for RuntimeApi {
 		unimplemented!("Not required for testing!")
 	}
 
-	fn into_storage_changes<
-		T: sp_api::ChangesTrieStorage<sp_api::HasherFor<Block>, sp_api::NumberFor<Block>>
-	>(
+	fn into_storage_changes(
 		&self,
 		_: &Self::StateBackend,
-		_: Option<&T>,
+		_: Option<&sp_api::ChangesTrieState<sp_api::HasherFor<Block>, sp_api::NumberFor<Block>>>,
 		_: <Block as sp_api::BlockT>::Hash,
 	) -> std::result::Result<sp_api::StorageChanges<Self::StateBackend, Block>, String>
 		where Self: Sized
diff --git a/client/basic-authorship/Cargo.toml b/client/basic-authorship/Cargo.toml
index 4cdef01afd46b..8fa0b9f5cc20e 100644
--- a/client/basic-authorship/Cargo.toml
+++ b/client/basic-authorship/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
-name = "sc-basic-authority"
-version = "2.0.0"
+name = "sc-basic-authorship"
+version = "0.8.0"
 authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2018"
 
@@ -12,13 +12,13 @@ sp-api = { version = "2.0.0", path = "../../primitives/api" }
 sp-runtime = { version = "2.0.0", path = "../../primitives/runtime" }
 sp-core = { version = "2.0.0", path = "../../primitives/core" }
 sp-blockchain = { version = "2.0.0", path = "../../primitives/blockchain" }
-sc-client = { version = "2.0.0", path = "../" }
+sc-client = { version = "0.8", path = "../" }
 sc-client-api = { version = "2.0.0", path = "../api" }
 sp-consensus = { version = "0.8", path = "../../primitives/consensus/common" }
 sp-inherents = { version = "2.0.0", path = "../../primitives/inherents" }
 sc-telemetry = { version = "2.0.0", path = "../telemetry" }
 sp-transaction-pool = { version = "2.0.0", path = "../../primitives/transaction-pool" }
-sc-block-builder = { version = "2.0.0", path = "../block-builder" }
+sc-block-builder = { version = "0.8", path = "../block-builder" }
 tokio-executor = { version = "0.2.0-alpha.6", features = ["blocking"] }
 
 [dev-dependencies]
diff --git a/client/basic-authorship/src/basic_authorship.rs b/client/basic-authorship/src/basic_authorship.rs
index 543428b073478..6c5b063020073 100644
--- a/client/basic-authorship/src/basic_authorship.rs
+++ b/client/basic-authorship/src/basic_authorship.rs
@@ -34,6 +34,7 @@ use sp_transaction_pool::{TransactionPool, InPoolTransaction};
 use sc_telemetry::{telemetry, CONSENSUS_INFO};
 use sc_block_builder::BlockBuilderApi;
 use sp_api::{ProvideRuntimeApi, ApiExt};
+use futures::prelude::*;
 
 /// Proposer factory.
 pub struct ProposerFactory<C, A> where A: TransactionPool {
@@ -59,7 +60,7 @@ impl<B, E, Block, RA, A> ProposerFactory<SubstrateClient<B, E, Block, RA>, A>
 		&mut self,
 		parent_header: &<Block as BlockT>::Header,
 		now: Box<dyn Fn() -> time::Instant + Send + Sync>,
-	) -> Result<Proposer<Block, SubstrateClient<B, E, Block, RA>, A>, sp_blockchain::Error> {
+	) -> Proposer<Block, SubstrateClient<B, E, Block, RA>, A> {
 		let parent_hash = parent_header.hash();
 
 		let id = BlockId::hash(parent_hash);
@@ -77,7 +78,7 @@ impl<B, E, Block, RA, A> ProposerFactory<SubstrateClient<B, E, Block, RA>, A>
 			}),
 		};
 
-		Ok(proposer)
+		proposer
 	}
 }
 
@@ -94,14 +95,15 @@ impl<B, E, Block, RA, A> sp_consensus::Environment<Block> for
 				BlockBuilderApi<Block, Error = sp_blockchain::Error> +
 				ApiExt<Block, StateBackend = backend::StateBackendFor<B, Block>>,
 {
+	type CreateProposer = future::Ready<Result<Self::Proposer, Self::Error>>;
 	type Proposer = Proposer<Block, SubstrateClient<B, E, Block, RA>, A>;
 	type Error = sp_blockchain::Error;
 
 	fn init(
 		&mut self,
 		parent_header: &<Block as BlockT>::Header,
-	) -> Result<Self::Proposer, sp_blockchain::Error> {
-		self.init_with_now(parent_header, Box::new(time::Instant::now))
+	) -> Self::CreateProposer {
+		future::ready(Ok(self.init_with_now(parent_header, Box::new(time::Instant::now))))
 	}
 }
 
@@ -203,6 +205,7 @@ impl<Block, B, E, RA, A> ProposerInner<Block, SubstrateClient<B, E, Block, RA>,
 		let pending_iterator = self.transaction_pool.ready();
 
 		debug!("Attempting to push transactions from the pool.");
+		debug!("Pool status: {:?}", self.transaction_pool.status());
 		for pending_tx in pending_iterator {
 			if (self.now)() > deadline {
 				debug!(
@@ -324,7 +327,7 @@ mod tests {
 				*value = new;
 				old
 			})
-		).unwrap();
+		);
 
 		// when
 		let deadline = time::Duration::from_secs(3);
@@ -359,7 +362,7 @@ mod tests {
 		let mut proposer = proposer_factory.init_with_now(
 			&client.header(&block_id).unwrap().unwrap(),
 			Box::new(move || time::Instant::now()),
-		).unwrap();
+		);
 
 		let deadline = time::Duration::from_secs(9);
 		let proposal = futures::executor::block_on(
@@ -372,9 +375,12 @@ mod tests {
 		api.execute_block(&block_id, proposal.block).unwrap();
 
 		let state = backend.state_at(block_id).unwrap();
-		let changes_trie_storage = backend.changes_trie_storage();
+		let changes_trie_state = backend::changes_tries_state_at_block(
+			&block_id,
+			backend.changes_trie_storage(),
+		).unwrap();
 
-		let storage_changes = api.into_storage_changes(&state, changes_trie_storage, genesis_hash)
+		let storage_changes = api.into_storage_changes(&state, changes_trie_state.as_ref(), genesis_hash)
 			.unwrap();
 
 		assert_eq!(
diff --git a/client/basic-authorship/src/lib.rs b/client/basic-authorship/src/lib.rs
index cf77c8a3f341a..f62134ce42aa7 100644
--- a/client/basic-authorship/src/lib.rs
+++ b/client/basic-authorship/src/lib.rs
@@ -19,7 +19,7 @@
 //! # Example
 //!
 //! ```
-//! # use sc_basic_authority::ProposerFactory;
+//! # use sc_basic_authorship::ProposerFactory;
 //! # use sp_consensus::{Environment, Proposer, RecordProof};
 //! # use sp_runtime::generic::BlockId;
 //! # use std::{sync::Arc, time::Duration};
@@ -34,9 +34,12 @@
 //! };
 //!
 //! // From this factory, we create a `Proposer`.
-//! let mut proposer = proposer_factory.init(
+//! let proposer = proposer_factory.init(
 //! 	&client.header(&BlockId::number(0)).unwrap().unwrap(),
-//! ).unwrap();
+//! );
+//!
+//! // The proposer is created asynchronously.
+//! let mut proposer = futures::executor::block_on(proposer).unwrap();
 //!
 //! // This `Proposer` allows us to create a block proposition.
 //! // The proposer will grab transactions from the transaction pool, and put them into the block.
diff --git a/client/block-builder/Cargo.toml b/client/block-builder/Cargo.toml
index 1dcc9b05f5eb9..29531c4288bed 100644
--- a/client/block-builder/Cargo.toml
+++ b/client/block-builder/Cargo.toml
@@ -1,11 +1,11 @@
 [package]
 name = "sc-block-builder"
-version = "2.0.0"
+version = "0.8.0"
 authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2018"
 
 [dependencies]
-sp-state-machine = { version = "2.0.0", path = "../../primitives/state-machine" }
+sp-state-machine = { version = "0.8", path = "../../primitives/state-machine" }
 sp-runtime = { version = "2.0.0", path = "../../primitives/runtime" }
 sp-api = { version = "2.0.0", path = "../../primitives/api" }
 sp-consensus = { version = "0.8.0", path = "../../primitives/consensus/common" }
diff --git a/client/block-builder/src/lib.rs b/client/block-builder/src/lib.rs
index f59f88f5ba237..9b403dead4415 100644
--- a/client/block-builder/src/lib.rs
+++ b/client/block-builder/src/lib.rs
@@ -191,14 +191,17 @@ where
 		let proof = self.api.extract_proof();
 
 		let state = self.backend.state_at(self.block_id)?;
-		let changes_trie_storage = self.backend.changes_trie_storage();
+		let changes_trie_state = backend::changes_tries_state_at_block(
+			&self.block_id,
+			self.backend.changes_trie_storage(),
+		)?;
 		let parent_hash = self.parent_hash;
 
 		// The unsafe is required because the consume requires that we drop/consume the inner api
 		// (what we do here).
 		let storage_changes = self.api.into_storage_changes(
 			&state,
-			changes_trie_storage,
+			changes_trie_state.as_ref(),
 			parent_hash,
 		);
 
diff --git a/client/chain-spec/src/chain_spec.rs b/client/chain-spec/src/chain_spec.rs
index 6e58083e8cc2e..81cbce5ea731c 100644
--- a/client/chain-spec/src/chain_spec.rs
+++ b/client/chain-spec/src/chain_spec.rs
@@ -70,7 +70,7 @@ impl<G: RuntimeGenesis> GenesisSource<G> {
 	}
 }
 
-impl<'a, G: RuntimeGenesis, E> BuildStorage for &'a ChainSpec<G, E> {
+impl<G: RuntimeGenesis, E> BuildStorage for ChainSpec<G, E> {
 	fn build_storage(&self) -> Result<Storage, String> {
 		match self.genesis.resolve()? {
 			Genesis::Runtime(gc) => gc.build_storage(),
diff --git a/client/cli/Cargo.toml b/client/cli/Cargo.toml
index 05fc019d0a9d9..1c1d967c7d8d5 100644
--- a/client/cli/Cargo.toml
+++ b/client/cli/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "sc-cli"
-version = "2.0.0"
+version = "0.8.0"
 authors = ["Parity Technologies <admin@parity.io>"]
 description = "Substrate CLI interface."
 edition = "2018"
@@ -16,8 +16,8 @@ time = "0.1.42"
 ansi_term = "0.12.1"
 lazy_static = "1.4.0"
 app_dirs = "1.2.1"
-tokio = "0.2.1"
-futures = { version = "0.3.1", features = ["compat"] }
+tokio = "0.2"
+futures = "0.3.1"
 fdlimit = "0.1.1"
 serde_json = "1.0.41"
 sp-panic-handler = { version = "2.0.0", path = "../../primitives/panic-handler" }
@@ -26,10 +26,10 @@ sp-blockchain = { version = "2.0.0", path = "../../primitives/blockchain" }
 sc-network = { version = "0.8", path = "../network" }
 sp-runtime = { version = "2.0.0", path = "../../primitives/runtime" }
 sp-core = { version = "2.0.0", path = "../../primitives/core" }
-sc-service = { version = "2.0.0", default-features = false, path = "../service" }
-sp-state-machine = { version = "2.0.0", path = "../../primitives/state-machine" }
+sc-service = { version = "0.8", default-features = false, path = "../service" }
+sp-state-machine = { version = "0.8", path = "../../primitives/state-machine" }
 sc-telemetry = { version = "2.0.0", path = "../telemetry" }
-prometheus-endpoint = { path = "../../utils/prometheus" }
+prometheus-exporter = { path = "../../utils/prometheus" }
 sp-keyring = { version = "2.0.0", path = "../../primitives/keyring" }
 names = "0.11.0"
 structopt = "=0.3.7"
diff --git a/client/cli/src/informant.rs b/client/cli/src/informant.rs
index de7c376f09fee..312e4017d5ff0 100644
--- a/client/cli/src/informant.rs
+++ b/client/cli/src/informant.rs
@@ -17,7 +17,7 @@
 //! Console informant. Prints sync progress and block events. Runs on the calling thread.
 
 use sc_client_api::BlockchainEvents;
-use futures::{StreamExt, TryStreamExt, FutureExt, future, compat::Stream01CompatExt};
+use futures::prelude::*;
 use log::{info, warn, trace};
 use sp_runtime::traits::Header;
 use sc_service::AbstractService;
@@ -33,8 +33,7 @@ pub fn build(service: &impl AbstractService) -> impl futures::Future<Output = ()
 
 	let display_notifications = service
 		.network_status(Duration::from_millis(5000))
-		.compat()
-		.try_for_each(move |(net_status, _)| {
+		.for_each(move |(net_status, _)| {
 			let info = client.usage_info();
 			if let Some(ref usage) = info.usage {
 				trace!(target: "usage", "Usage statistics: {}", usage);
@@ -42,7 +41,7 @@ pub fn build(service: &impl AbstractService) -> impl futures::Future<Output = ()
 				trace!(target: "usage", "Usage statistics not displayed as backend does not provide it")
 			}
 			display.display(&info, net_status);
-			future::ok(())
+			future::ready(())
 		});
 
 	let client = service.client();
diff --git a/client/cli/src/informant/display.rs b/client/cli/src/informant/display.rs
index c69cce143a386..199635e7c7883 100644
--- a/client/cli/src/informant/display.rs
+++ b/client/cli/src/informant/display.rs
@@ -18,19 +18,9 @@ use ansi_term::Colour;
 use sc_client_api::ClientInfo;
 use log::info;
 use sc_network::SyncState;
-use sp_runtime::traits::{
-	Block as BlockT, CheckedDiv, NumberFor, Zero, Saturating, UniqueSaturatedInto
-};
+use sp_runtime::traits::{Block as BlockT, CheckedDiv, NumberFor, Zero, Saturating};
 use sc_service::NetworkStatus;
 use std::{convert::{TryFrom, TryInto}, fmt, time};
-use prometheus_endpoint::{create_gauge, Gauge, U64};
-
-prometheus_endpoint::lazy_static! {
-	pub static ref SYNC_TARGET: Gauge<U64> = create_gauge(
-		"sync_target_number",
-		"block sync target number"
-	);
-}
 
 /// State of the informant display system.
 ///
@@ -73,10 +63,7 @@ impl<B: BlockT> InformantDisplay<B> {
 		let (status, target) = match (net_status.sync_state, net_status.best_seen_block) {
 			(SyncState::Idle, _) => ("Idle".into(), "".into()),
 			(SyncState::Downloading, None) => (format!("Syncing{}", speed), "".into()),
-			(SyncState::Downloading, Some(n)) => {
-				SYNC_TARGET.set(n.unique_saturated_into() as u64);
-				(format!("Syncing{}", speed), format!(", target=#{}", n))
-			}
+			(SyncState::Downloading, Some(n)) => (format!("Syncing{}", speed), format!(", target=#{}", n)),
 		};
 
 		info!(
diff --git a/client/cli/src/lib.rs b/client/cli/src/lib.rs
index 96bf17999cf3e..79afaa03b4269 100644
--- a/client/cli/src/lib.rs
+++ b/client/cli/src/lib.rs
@@ -61,7 +61,7 @@ pub use traits::GetSharedParams;
 use app_dirs::{AppInfo, AppDataType};
 use log::info;
 use lazy_static::lazy_static;
-use futures::{Future, compat::Future01CompatExt, executor::block_on};
+use futures::{Future, executor::block_on};
 use sc_telemetry::TelemetryEndpoints;
 use sp_runtime::generic::BlockId;
 use sp_runtime::traits::{Block as BlockT, Header as HeaderT};
@@ -142,8 +142,13 @@ pub fn load_spec<F, G, E>(cli: &SharedParams, factory: F) -> error::Result<Chain
 	Ok(spec)
 }
 
-fn base_path(cli: &SharedParams, version: &VersionInfo) -> PathBuf {
+fn base_path(
+	cli: &SharedParams,
+	version: &VersionInfo,
+	default_base_path: Option<PathBuf>,
+) -> PathBuf {
 	cli.base_path.clone()
+		.or(default_base_path)
 		.unwrap_or_else(||
 			app_dirs::get_app_root(
 				AppDataType::UserData,
@@ -295,6 +300,78 @@ impl<'a, CC, RP> ParseAndPrepare<'a, CC, RP> where CC: GetSharedParams {
 	}
 }
 
+impl<'a, CC, RP> ParseAndPrepare<'a, CC, RP> {
+	/// Convert ParseAndPrepare to Configuration
+	pub fn into_configuration<C, G, E, S>(
+		self,
+		spec_factory: S,
+		default_base_path: Option<PathBuf>,
+	) -> error::Result<Option<Configuration<C, G, E>>>
+	where
+		C: Default,
+		G: RuntimeGenesis,
+		E: ChainSpecExtension,
+		S: FnOnce(&str) -> Result<Option<ChainSpec<G, E>>, String>,
+	{
+		match self {
+			ParseAndPrepare::Run(c) =>
+				Some(create_run_node_config(
+					c.params.left,
+					spec_factory,
+					c.impl_name,
+					c.version,
+					default_base_path,
+				)).transpose(),
+			ParseAndPrepare::BuildSpec(c) => {
+				let spec = load_spec(&c.params.shared_params, spec_factory)?;
+
+				Some(create_build_spec_config(
+					&spec,
+					&c.params.shared_params,
+					c.version,
+					default_base_path,
+				)).transpose()
+			},
+			ParseAndPrepare::ExportBlocks(c) =>
+				Some(create_config_with_db_path(
+					spec_factory,
+					&c.params.shared_params,
+					c.version,
+					default_base_path,
+				)).transpose(),
+			ParseAndPrepare::ImportBlocks(c) =>
+				Some(create_config_with_db_path(
+					spec_factory,
+					&c.params.shared_params,
+					c.version,
+					default_base_path,
+				)).transpose(),
+			ParseAndPrepare::CheckBlock(c) =>
+				Some(create_config_with_db_path(
+					spec_factory,
+					&c.params.shared_params,
+					c.version,
+					default_base_path,
+				)).transpose(),
+			ParseAndPrepare::PurgeChain(c) =>
+				Some(create_config_with_db_path(
+					spec_factory,
+					&c.params.shared_params,
+					c.version,
+					default_base_path,
+				)).transpose(),
+			ParseAndPrepare::RevertChain(c) =>
+				Some(create_config_with_db_path(
+					spec_factory,
+					&c.params.shared_params,
+					c.version,
+					default_base_path,
+				)).transpose(),
+			ParseAndPrepare::CustomCommand(_) => Ok(None),
+		}
+	}
+}
+
 /// Command ready to run the main client.
 pub struct ParseAndPrepareRun<'a, RP> {
 	params: MergeParameters<RunCmd, RP>,
@@ -321,7 +398,11 @@ impl<'a, RP> ParseAndPrepareRun<'a, RP> {
 		RS: FnOnce(Exit, RunCmd, RP, Configuration<C, G, CE>) -> Result<(), E>
 	{
 		let config = create_run_node_config(
-			self.params.left.clone(), spec_factory, self.impl_name, self.version,
+			self.params.left.clone(),
+			spec_factory,
+			self.impl_name,
+			self.version,
+			None,
 		)?;
 
 		run_service(exit, self.params.left, self.params.right, config).map_err(Into::into)
@@ -350,11 +431,12 @@ impl<'a> ParseAndPrepareBuildSpec<'a> {
 		let mut spec = load_spec(&self.params.shared_params, spec_factory)?;
 
 		if spec.boot_nodes().is_empty() && !self.params.disable_default_bootnode {
-			let base_path = base_path(&self.params.shared_params, self.version);
-			let cfg = sc_service::Configuration::<C,_,_>::default_with_spec_and_base_path(
-				spec.clone(),
-				Some(base_path),
-			);
+			let cfg = create_build_spec_config::<C, _, _>(
+				&spec,
+				&self.params.shared_params,
+				self.version,
+				None,
+			)?;
 			let node_key = node_key_config(
 				self.params.node_key_params,
 				&Some(cfg.in_chain_config_dir(DEFAULT_NETWORK_CONFIG_PATH).expect("We provided a base_path"))
@@ -401,7 +483,13 @@ impl<'a> ParseAndPrepareExport<'a> {
 		E: ChainSpecExtension,
 		Exit: IntoExit
 	{
-		let config = create_config_with_db_path(spec_factory, &self.params.shared_params, self.version)?;
+		let mut config = create_config_with_db_path(
+			spec_factory,
+			&self.params.shared_params,
+			self.version,
+			None,
+		)?;
+		fill_config_keystore_in_memory(&mut config)?;
 
 		if let DatabaseConfig::Path { ref path, .. } = &config.database {
 			info!("DB path: {}", path.display());
@@ -426,8 +514,7 @@ impl<'a> ParseAndPrepareExport<'a> {
 		});
 
 		let mut export_fut = builder(config)?
-			.export_blocks(file, from.into(), to, json)
-			.compat();
+			.export_blocks(file, from.into(), to, json);
 		let fut = futures::future::poll_fn(|cx| {
 			if exit_recv.try_recv().is_ok() {
 				return Poll::Ready(Ok(()));
@@ -463,7 +550,12 @@ impl<'a> ParseAndPrepareImport<'a> {
 		E: ChainSpecExtension,
 		Exit: IntoExit
 	{
-		let mut config = create_config_with_db_path(spec_factory, &self.params.shared_params, self.version)?;
+		let mut config = create_config_with_db_path(
+			spec_factory,
+			&self.params.shared_params,
+			self.version,
+			None,
+		)?;
 		fill_import_params(&mut config, &self.params.import_params, sc_service::Roles::FULL)?;
 
 		let file: Box<dyn ReadPlusSeek + Send> = match self.params.input {
@@ -485,8 +577,7 @@ impl<'a> ParseAndPrepareImport<'a> {
 		});
 
 		let mut import_fut = builder(config)?
-			.import_blocks(file, false)
-			.compat();
+			.import_blocks(file, false);
 		let fut = futures::future::poll_fn(|cx| {
 			if exit_recv.try_recv().is_ok() {
 				return Poll::Ready(Ok(()));
@@ -523,8 +614,14 @@ impl<'a> CheckBlock<'a> {
 			E: ChainSpecExtension,
 			Exit: IntoExit
 	{
-		let mut config = create_config_with_db_path(spec_factory, &self.params.shared_params, self.version)?;
+		let mut config = create_config_with_db_path(
+			spec_factory,
+			&self.params.shared_params,
+			self.version,
+			None,
+		)?;
 		fill_import_params(&mut config, &self.params.import_params, sc_service::Roles::FULL)?;
+		fill_config_keystore_in_memory(&mut config)?;
 
 		let input = if self.params.input.starts_with("0x") { &self.params.input[2..] } else { &self.params.input[..] };
 		let block_id = match FromStr::from_str(input) {
@@ -537,8 +634,7 @@ impl<'a> CheckBlock<'a> {
 
 		let start = std::time::Instant::now();
 		let check = builder(config)?
-			.check_block(block_id)
-			.compat();
+			.check_block(block_id);
 		let mut runtime = tokio::runtime::Runtime::new().unwrap();
 		runtime.block_on(check)?;
 		println!("Completed in {} ms.", start.elapsed().as_millis());
@@ -562,9 +658,13 @@ impl<'a> ParseAndPreparePurge<'a> {
 		G: RuntimeGenesis,
 		E: ChainSpecExtension,
 	{
-		let config = create_config_with_db_path::<(), _, _, _>(
-			spec_factory, &self.params.shared_params, self.version
+		let mut config = create_config_with_db_path::<(), _, _, _>(
+			spec_factory,
+			&self.params.shared_params,
+			self.version,
+			None,
 		)?;
+		fill_config_keystore_in_memory(&mut config)?;
 		let db_path = match config.database {
 			DatabaseConfig::Path { path, .. } => path,
 			_ => {
@@ -626,9 +726,14 @@ impl<'a> ParseAndPrepareRevert<'a> {
 		G: RuntimeGenesis,
 		E: ChainSpecExtension,
 	{
-		let config = create_config_with_db_path(
-			spec_factory, &self.params.shared_params, self.version
+		let mut config = create_config_with_db_path(
+			spec_factory,
+			&self.params.shared_params,
+			self.version,
+			None,
 		)?;
+		fill_config_keystore_in_memory(&mut config)?;
+
 		let blocks = self.params.num.parse()?;
 		builder(config)?.revert_chain(blocks)?;
 		Ok(())
@@ -752,6 +857,16 @@ fn input_keystore_password() -> Result<String, String> {
 		.map_err(|e| format!("{:?}", e))
 }
 
+/// Use in memory keystore config when it is not required at all.
+fn fill_config_keystore_in_memory<C, G, E>(config: &mut sc_service::Configuration<C, G, E>)
+	-> Result<(), String>
+{
+	match &mut config.keystore {
+		cfg @ KeystoreConfig::None => { *cfg = KeystoreConfig::InMemory; Ok(()) },
+		_ => Err("Keystore config specified when it should not be!".into()),
+	}
+}
+
 /// Fill the password field of the given config instance.
 fn fill_config_keystore_password_and_path<C, G, E>(
 	config: &mut sc_service::Configuration<C, G, E>,
@@ -840,7 +955,11 @@ pub fn fill_import_params<C, G, E>(
 }
 
 fn create_run_node_config<C, G, E, S>(
-	cli: RunCmd, spec_factory: S, impl_name: &'static str, version: &VersionInfo,
+	cli: RunCmd,
+	spec_factory: S,
+	impl_name: &'static str,
+	version: &VersionInfo,
+	default_base_path: Option<PathBuf>,
 ) -> error::Result<Configuration<C, G, E>>
 where
 	C: Default,
@@ -848,7 +967,12 @@ where
 	E: ChainSpecExtension,
 	S: FnOnce(&str) -> Result<Option<ChainSpec<G, E>>, String>,
 {
-	let mut config = create_config_with_db_path(spec_factory, &cli.shared_params, &version)?;
+	let mut config = create_config_with_db_path(
+		spec_factory,
+		&cli.shared_params,
+		&version,
+		default_base_path,
+	)?;
 
 	fill_config_keystore_password_and_path(&mut config, &cli)?;
 
@@ -925,7 +1049,7 @@ where
 	config.rpc_http = Some(parse_address(&format!("{}:{}", rpc_interface, 9933), cli.rpc_port)?);
 	config.rpc_ws = Some(parse_address(&format!("{}:{}", ws_interface, 9944), cli.ws_port)?);
 	config.prometheus_port = Some(
-		parse_address(&format!("{}:{}", prometheus_interface, 9955), cli.prometheus_port)?
+		parse_address(&format!("{}:{}", prometheus_interface, 9615), cli.prometheus_port)?
 	);
 
 	config.rpc_ws_max_connections = cli.ws_max_connections;
@@ -982,7 +1106,10 @@ fn interface_str(
 
 /// Creates a configuration including the database path.
 pub fn create_config_with_db_path<C, G, E, S>(
-	spec_factory: S, cli: &SharedParams, version: &VersionInfo,
+	spec_factory: S,
+	cli: &SharedParams,
+	version: &VersionInfo,
+	default_base_path: Option<PathBuf>,
 ) -> error::Result<Configuration<C, G, E>>
 where
 	C: Default,
@@ -991,7 +1118,7 @@ where
 	S: FnOnce(&str) -> Result<Option<ChainSpec<G, E>>, String>,
 {
 	let spec = load_spec(cli, spec_factory)?;
-	let base_path = base_path(cli, version);
+	let base_path = base_path(cli, version, default_base_path);
 
 	let mut config = sc_service::Configuration::default_with_spec_and_base_path(
 		spec.clone(),
@@ -1006,6 +1133,27 @@ where
 	Ok(config)
 }
 
+/// Creates a configuration including the base path and the shared params
+fn create_build_spec_config<C, G, E>(
+	spec: &ChainSpec<G, E>,
+	cli: &SharedParams,
+	version: &VersionInfo,
+	default_base_path: Option<PathBuf>,
+) -> error::Result<Configuration<C, G, E>>
+where
+	C: Default,
+	G: RuntimeGenesis,
+	E: ChainSpecExtension,
+{
+	let base_path = base_path(&cli, version, default_base_path);
+	let cfg = sc_service::Configuration::<C,_,_>::default_with_spec_and_base_path(
+		spec.clone(),
+		Some(base_path),
+	);
+
+	Ok(cfg)
+}
+
 /// Internal trait used to cast to a dynamic type that implements Read and Seek.
 trait ReadPlusSeek: Read + Seek {}
 
@@ -1243,6 +1391,7 @@ mod tests {
 				|_| Ok(Some(chain_spec.clone())),
 				"test",
 				&version_info,
+				None,
 			).unwrap();
 
 			let expected_path = match keystore_path {
@@ -1253,4 +1402,44 @@ mod tests {
 			assert_eq!(expected_path, node_config.keystore.path().unwrap().to_owned());
 		}
 	}
+
+	#[test]
+	fn parse_and_prepare_into_configuration() {
+		let chain_spec = ChainSpec::from_genesis(
+			"test",
+			"test-id",
+			|| (),
+			Vec::new(),
+			None,
+			None,
+			None,
+			None,
+		);
+		let version = VersionInfo {
+			name: "test",
+			version: "42",
+			commit: "234234",
+			executable_name: "test",
+			description: "cool test",
+			author: "universe",
+			support_url: "com",
+		};
+		let spec_factory = |_: &str| Ok(Some(chain_spec.clone()));
+
+		let args = vec!["substrate", "--dev", "--state-cache-size=42"];
+		let pnp = parse_and_prepare::<NoCustom, NoCustom, _>(&version, "test", args);
+		let config = pnp.into_configuration::<(), _, _, _>(spec_factory, None).unwrap().unwrap();
+		assert_eq!(config.roles, sc_service::Roles::AUTHORITY);
+		assert_eq!(config.state_cache_size, 42);
+
+		let args = vec!["substrate", "import-blocks", "--dev"];
+		let pnp = parse_and_prepare::<NoCustom, NoCustom, _>(&version, "test", args);
+		let config = pnp.into_configuration::<(), _, _, _>(spec_factory, None).unwrap().unwrap();
+		assert_eq!(config.roles, sc_service::Roles::FULL);
+
+		let args = vec!["substrate", "--base-path=/foo"];
+		let pnp = parse_and_prepare::<NoCustom, NoCustom, _>(&version, "test", args);
+		let config = pnp.into_configuration::<(), _, _, _>(spec_factory, Some("/bar".into())).unwrap().unwrap();
+		assert_eq!(config.config_dir, Some("/foo".into()));
+	}
 }
diff --git a/client/consensus/aura/Cargo.toml b/client/consensus/aura/Cargo.toml
index ddae989b4170f..3d4c5a9157bef 100644
--- a/client/consensus/aura/Cargo.toml
+++ b/client/consensus/aura/Cargo.toml
@@ -9,13 +9,12 @@ edition = "2018"
 sp-application-crypto = { version = "2.0.0", path = "../../../primitives/application-crypto" }
 sp-consensus-aura = { version = "0.8", path = "../../../primitives/consensus/aura" }
 sp-block-builder = { version = "2.0.0", path = "../../../primitives/block-builder" }
-sc-client = { version = "2.0.0", path = "../../" }
+sc-client = { version = "0.8", path = "../../" }
 sc-client-api = { version = "2.0.0", path = "../../api" }
 codec = { package = "parity-scale-codec", version = "1.0.0" }
 sp-consensus = { version = "0.8", path = "../../../primitives/consensus/common" }
 derive_more = "0.99.2"
-futures = { version = "0.3.1", features = ["compat"] }
-futures01 = { package = "futures", version = "0.1" }
+futures = "0.3.1"
 futures-timer = "0.4.0"
 sp-inherents = { version = "2.0.0", path = "../../../primitives/inherents" }
 sc-keystore = { version = "2.0.0", path = "../../keystore" }
@@ -33,11 +32,12 @@ sc-telemetry = { version = "2.0.0", path = "../../telemetry" }
 
 [dev-dependencies]
 sp-keyring = { version = "2.0.0", path = "../../../primitives/keyring" }
-sc-executor = { version = "2.0.0", path = "../../executor" }
+sc-executor = { version = "0.8", path = "../../executor" }
 sc-network = { version = "0.8", path = "../../network" }
-sc-network-test = { version = "2.0.0", path = "../../network/test" }
-sc-service = { version = "2.0.0", path = "../../service" }
+sc-network-test = { version = "0.8.0", path = "../../network/test" }
+sc-service = { version = "0.8", path = "../../service" }
 substrate-test-runtime-client = { version = "2.0.0", path = "../../../test-utils/runtime/client" }
 tokio = "0.1.22"
 env_logger = "0.7.0"
 tempfile = "3.1.0"
+futures01 = { package = "futures", version = "0.1" }
diff --git a/client/consensus/aura/src/lib.rs b/client/consensus/aura/src/lib.rs
index 13a4c5a777144..95dc08afaf5ef 100644
--- a/client/consensus/aura/src/lib.rs
+++ b/client/consensus/aura/src/lib.rs
@@ -153,7 +153,7 @@ pub fn start_aura<B, C, SC, E, I, P, SO, CAW, Error>(
 	force_authoring: bool,
 	keystore: KeyStorePtr,
 	can_author_with: CAW,
-) -> Result<impl futures01::Future<Item = (), Error = ()>, sp_consensus::Error> where
+) -> Result<impl Future<Output = ()>, sp_consensus::Error> where
 	B: BlockT,
 	C: ProvideRuntimeApi<B> + BlockOf + ProvideCache<B> + AuxStore + Send + Sync,
 	C::Api: AuraApi<B, AuthorityId<P>>,
@@ -189,7 +189,7 @@ pub fn start_aura<B, C, SC, E, I, P, SO, CAW, Error>(
 		inherent_data_providers,
 		AuraSlotCompatible,
 		can_author_with,
-	).map(|()| Ok::<(), ()>(())).compat())
+	))
 }
 
 struct AuraWorker<C, E, I, P, SO> {
@@ -217,6 +217,9 @@ impl<B, C, E, I, P, Error, SO> sc_consensus_slots::SimpleSlotWorker<B> for AuraW
 {
 	type BlockImport = I;
 	type SyncOracle = SO;
+	type CreateProposer = Pin<Box<
+		dyn Future<Output = Result<E::Proposer, sp_consensus::Error>> + Send + 'static
+	>>;
 	type Proposer = E::Proposer;
 	type Claim = P;
 	type EpochData = Vec<AuthorityId<P>>;
@@ -302,10 +305,10 @@ impl<B, C, E, I, P, Error, SO> sc_consensus_slots::SimpleSlotWorker<B> for AuraW
 		&mut self.sync_oracle
 	}
 
-	fn proposer(&mut self, block: &B::Header) -> Result<Self::Proposer, sp_consensus::Error> {
-		self.env.init(block).map_err(|e| {
+	fn proposer(&mut self, block: &B::Header) -> Self::CreateProposer {
+		Box::pin(self.env.init(block).map_err(|e| {
 			sp_consensus::Error::ClientImport(format!("{:?}", e)).into()
-		})
+		}))
 	}
 
 	fn proposing_remaining_duration(
@@ -672,19 +675,21 @@ fn initialize_authorities_cache<A, B, C>(client: &C) -> Result<(), ConsensusErro
 	};
 
 	// check if we already have initialized the cache
+	let map_err = |error| sp_consensus::Error::from(sp_consensus::Error::ClientImport(
+		format!(
+			"Error initializing authorities cache: {}",
+			error,
+		)));
+
 	let genesis_id = BlockId::Number(Zero::zero());
 	let genesis_authorities: Option<Vec<A>> = cache
 		.get_at(&well_known_cache_keys::AUTHORITIES, &genesis_id)
+		.unwrap_or(None)
 		.and_then(|(_, _, v)| Decode::decode(&mut &v[..]).ok());
 	if genesis_authorities.is_some() {
 		return Ok(());
 	}
 
-	let map_err = |error| sp_consensus::Error::from(sp_consensus::Error::ClientImport(
-		format!(
-			"Error initializing authorities cache: {}",
-			error,
-		)));
 	let genesis_authorities = authorities(client, &genesis_id)?;
 	cache.initialize(&well_known_cache_keys::AUTHORITIES, genesis_authorities.encode())
 		.map_err(map_err)?;
@@ -703,6 +708,7 @@ fn authorities<A, B, C>(client: &C, at: &BlockId<B>) -> Result<Vec<A>, Consensus
 		.cache()
 		.and_then(|cache| cache
 			.get_at(&well_known_cache_keys::AUTHORITIES, at)
+			.unwrap_or(None)
 			.and_then(|(_, _, v)| Decode::decode(&mut &v[..]).ok())
 		)
 		.or_else(|| AuraApi::authorities(&*client.runtime_api(), at).ok())
@@ -874,12 +880,13 @@ mod tests {
 
 	impl Environment<TestBlock> for DummyFactory {
 		type Proposer = DummyProposer;
+		type CreateProposer = futures::future::Ready<Result<DummyProposer, Error>>;
 		type Error = Error;
 
 		fn init(&mut self, parent_header: &<TestBlock as BlockT>::Header)
-			-> Result<DummyProposer, Error>
+			-> Self::CreateProposer
 		{
-			Ok(DummyProposer(parent_header.number + 1, self.0.clone()))
+			futures::future::ready(Ok(DummyProposer(parent_header.number + 1, self.0.clone())))
 		}
 	}
 
@@ -1019,7 +1026,10 @@ mod tests {
 				false,
 				keystore,
 				sp_consensus::AlwaysCanAuthor,
-			).expect("Starts aura");
+			)
+				.expect("Starts aura")
+				.unit_error()
+				.compat();
 
 			runtime.spawn(aura);
 		}
@@ -1030,7 +1040,7 @@ mod tests {
 		}));
 
 		runtime.block_on(future::join_all(import_notifications)
-			.map(|_| Ok::<(), ()>(())).compat()).unwrap();
+			.unit_error().compat()).unwrap();
 	}
 
 	#[test]
diff --git a/client/consensus/babe/Cargo.toml b/client/consensus/babe/Cargo.toml
index eb2875b3d37ff..55b0e0cf20217 100644
--- a/client/consensus/babe/Cargo.toml
+++ b/client/consensus/babe/Cargo.toml
@@ -20,7 +20,7 @@ sp-timestamp = { version = "2.0.0", path = "../../../primitives/timestamp" }
 sc-telemetry = { version = "2.0.0", path = "../../telemetry" }
 sc-keystore = { version = "2.0.0", path = "../../keystore" }
 sc-client-api = { version = "2.0.0", path = "../../api" }
-sc-client = { version = "2.0.0", path = "../../" }
+sc-client = { version = "0.8", path = "../../" }
 sp-api = { version = "2.0.0", path = "../../../primitives/api" }
 sp-block-builder = { version = "2.0.0", path = "../../../primitives/block-builder" }
 sp-blockchain = { version = "2.0.0", path = "../../../primitives/blockchain" }
@@ -29,8 +29,7 @@ sc-consensus-uncles = { version = "0.8", path = "../uncles" }
 sc-consensus-slots = { version = "0.8", path = "../slots" }
 sp-runtime = { version = "2.0.0", path = "../../../primitives/runtime" }
 fork-tree = { version = "2.0.0", path = "../../../utils/fork-tree" }
-futures = { version = "0.3.1", features = ["compat"] }
-futures01 = { package = "futures", version = "0.1" }
+futures = "0.3.1"
 futures-timer = "0.4.0"
 parking_lot = "0.9.0"
 log = "0.4.8"
@@ -42,15 +41,16 @@ derive_more = "0.99.2"
 
 [dev-dependencies]
 sp-keyring = { version = "2.0.0", path = "../../../primitives/keyring" }
-sc-executor = { version = "2.0.0", path = "../../executor" }
+sc-executor = { version = "0.8", path = "../../executor" }
 sc-network = { version = "0.8", path = "../../network" }
-sc-network-test = { version = "2.0.0", path = "../../network/test" }
-sc-service = { version = "2.0.0", path = "../../service" }
+sc-network-test = { version = "0.8.0", path = "../../network/test" }
+sc-service = { version = "0.8", path = "../../service" }
 substrate-test-runtime-client = { version = "2.0.0", path = "../../../test-utils/runtime/client" }
-sc-block-builder = { version = "2.0.0", path = "../../block-builder" }
+sc-block-builder = { version = "0.8", path = "../../block-builder" }
 tokio = "0.1.22"
 env_logger = "0.7.0"
 tempfile = "3.1.0"
+futures01 = { package = "futures", version = "0.1" }
 
 [features]
 test-helpers = []
diff --git a/client/consensus/babe/src/lib.rs b/client/consensus/babe/src/lib.rs
index bbf19b706601f..770f8a4eec6e2 100644
--- a/client/consensus/babe/src/lib.rs
+++ b/client/consensus/babe/src/lib.rs
@@ -289,7 +289,7 @@ pub fn start_babe<B, C, SC, E, I, SO, CAW, Error>(BabeParams {
 	babe_link,
 	can_author_with,
 }: BabeParams<B, C, E, I, SO, SC, CAW>) -> Result<
-	impl futures01::Future<Item=(), Error=()>,
+	impl futures::Future<Output=()>,
 	sp_consensus::Error,
 > where
 	B: BlockT,
@@ -325,7 +325,7 @@ pub fn start_babe<B, C, SC, E, I, SO, CAW, Error>(BabeParams {
 	)?;
 
 	babe_info!("Starting BABE Authorship worker");
-	let slot_worker = sc_consensus_slots::start_slot_worker(
+	Ok(sc_consensus_slots::start_slot_worker(
 		config.0,
 		select_chain,
 		worker,
@@ -333,9 +333,7 @@ pub fn start_babe<B, C, SC, E, I, SO, CAW, Error>(BabeParams {
 		inherent_data_providers,
 		babe_link.time_source,
 		can_author_with,
-	);
-
-	Ok(slot_worker.map(|_| Ok::<(), ()>(())).compat())
+	))
 }
 
 struct BabeWorker<B: BlockT, C, E, I, SO> {
@@ -365,6 +363,9 @@ impl<B, C, E, I, Error, SO> sc_consensus_slots::SimpleSlotWorker<B> for BabeWork
 	type EpochData = Epoch;
 	type Claim = (BabePreDigest, AuthorityPair);
 	type SyncOracle = SO;
+	type CreateProposer = Pin<Box<
+		dyn Future<Output = Result<E::Proposer, sp_consensus::Error>> + Send + 'static
+	>>;
 	type Proposer = E::Proposer;
 	type BlockImport = I;
 
@@ -468,10 +469,10 @@ impl<B, C, E, I, Error, SO> sc_consensus_slots::SimpleSlotWorker<B> for BabeWork
 		&mut self.sync_oracle
 	}
 
-	fn proposer(&mut self, block: &B::Header) -> Result<Self::Proposer, sp_consensus::Error> {
-		self.env.init(block).map_err(|e| {
+	fn proposer(&mut self, block: &B::Header) -> Self::CreateProposer {
+		Box::pin(self.env.init(block).map_err(|e| {
 			sp_consensus::Error::ClientImport(format!("{:?}", e))
-		})
+		}))
 	}
 
 	fn proposing_remaining_duration(
diff --git a/client/consensus/babe/src/tests.rs b/client/consensus/babe/src/tests.rs
index 2ddb67fe4796e..880e028000b42 100644
--- a/client/consensus/babe/src/tests.rs
+++ b/client/consensus/babe/src/tests.rs
@@ -72,23 +72,24 @@ struct DummyProposer {
 }
 
 impl Environment<TestBlock> for DummyFactory {
+	type CreateProposer = future::Ready<Result<DummyProposer, Error>>;
 	type Proposer = DummyProposer;
 	type Error = Error;
 
 	fn init(&mut self, parent_header: &<TestBlock as BlockT>::Header)
-		-> Result<DummyProposer, Error>
+		-> Self::CreateProposer
 	{
 
 		let parent_slot = crate::find_pre_digest::<TestBlock>(parent_header)
 			.expect("parent header has a pre-digest")
 			.slot_number();
 
-		Ok(DummyProposer {
+		future::ready(Ok(DummyProposer {
 			factory: self.clone(),
 			parent_hash: parent_header.hash(),
 			parent_number: *parent_header.number(),
 			parent_slot,
-		})
+		}))
 	}
 }
 
@@ -419,7 +420,7 @@ fn run_one_test(
 			babe_link: data.link.clone(),
 			keystore,
 			can_author_with: sp_consensus::AlwaysCanAuthor,
-		}).expect("Starts babe"));
+		}).expect("Starts babe").unit_error().compat());
 	}
 
 	runtime.spawn(futures01::future::poll_fn(move || {
@@ -428,7 +429,7 @@ fn run_one_test(
 	}));
 
 	runtime.block_on(future::join_all(import_notifications)
-		.map(|_| Ok::<(), ()>(())).compat()).unwrap();
+		.unit_error().compat()).unwrap();
 }
 
 #[test]
@@ -547,7 +548,7 @@ fn propose_and_import_block<Transaction>(
 	proposer_factory: &mut DummyFactory,
 	block_import: &mut BoxBlockImport<TestBlock, Transaction>,
 ) -> sp_core::H256 {
-	let mut proposer = proposer_factory.init(parent).unwrap();
+	let mut proposer = futures::executor::block_on(proposer_factory.init(parent)).unwrap();
 
 	let slot_number = slot_number.unwrap_or_else(|| {
 		let parent_pre_digest = find_pre_digest::<TestBlock>(parent).unwrap();
diff --git a/client/consensus/pow/src/lib.rs b/client/consensus/pow/src/lib.rs
index 5c491057e576c..2ea0cbdf0f7ae 100644
--- a/client/consensus/pow/src/lib.rs
+++ b/client/consensus/pow/src/lib.rs
@@ -486,7 +486,7 @@ fn mine_loop<B: BlockT, C, Algorithm, E, SO, S, CAW>(
 		}
 
 		let mut aux = PowAux::read(client, &best_hash)?;
-		let mut proposer = env.init(&best_header)
+		let mut proposer = futures::executor::block_on(env.init(&best_header))
 			.map_err(|e| Error::Environment(format!("{:?}", e)))?;
 
 		let inherent_data = inherent_data_providers
diff --git a/client/consensus/slots/Cargo.toml b/client/consensus/slots/Cargo.toml
index 3f1a572249899..89ee14b8fa463 100644
--- a/client/consensus/slots/Cargo.toml
+++ b/client/consensus/slots/Cargo.toml
@@ -12,7 +12,7 @@ sc-client-api = { version = "2.0.0", path = "../../api" }
 sp-core = { version = "2.0.0", path = "../../../primitives/core" }
 sp-blockchain = { version = "2.0.0", path = "../../../primitives/blockchain" }
 sp-runtime = { version = "2.0.0", path = "../../../primitives/runtime" }
-sp-state-machine = { version = "2.0.0", path = "../../../primitives/state-machine" }
+sp-state-machine = { version = "0.8.0", path = "../../../primitives/state-machine" }
 sp-api = { version = "2.0.0", path = "../../../primitives/api" }
 sc-telemetry = { version = "2.0.0", path = "../../telemetry" }
 sp-consensus = { version = "0.8", path = "../../../primitives/consensus/common" }
diff --git a/client/consensus/slots/src/lib.rs b/client/consensus/slots/src/lib.rs
index a69c710a7e944..3aa243af72b06 100644
--- a/client/consensus/slots/src/lib.rs
+++ b/client/consensus/slots/src/lib.rs
@@ -70,6 +70,10 @@ pub trait SimpleSlotWorker<B: BlockT> {
 	/// A handle to a `SyncOracle`.
 	type SyncOracle: SyncOracle;
 
+	/// The type of future resolving to the proposer.
+	type CreateProposer: Future<Output = Result<Self::Proposer, sp_consensus::Error>>
+		+ Send + Unpin + 'static;
+
 	/// The type of proposer to use to build blocks.
 	type Proposer: Proposer<B>;
 
@@ -129,7 +133,7 @@ pub trait SimpleSlotWorker<B: BlockT> {
 	fn sync_oracle(&mut self) -> &mut Self::SyncOracle;
 
 	/// Returns a `Proposer` to author on top of the given block.
-	fn proposer(&mut self, block: &B::Header) -> Result<Self::Proposer, sp_consensus::Error>;
+	fn proposer(&mut self, block: &B::Header) -> Self::CreateProposer;
 
 	/// Remaining duration of the slot.
 	fn slot_remaining_duration(&self, slot_info: &SlotInfo) -> Duration {
@@ -216,32 +220,30 @@ pub trait SimpleSlotWorker<B: BlockT> {
 			"timestamp" => timestamp,
 		);
 
-		let mut proposer = match self.proposer(&chain_head) {
-			Ok(proposer) => proposer,
-			Err(err) => {
-				warn!("Unable to author block in slot {:?}: {:?}", slot_number, err);
+		let awaiting_proposer = self.proposer(&chain_head).map_err(move |err| {
+			warn!("Unable to author block in slot {:?}: {:?}", slot_number, err);
 
-				telemetry!(CONSENSUS_WARN; "slots.unable_authoring_block";
-					"slot" => slot_number, "err" => ?err
-				);
+			telemetry!(CONSENSUS_WARN; "slots.unable_authoring_block";
+				"slot" => slot_number, "err" => ?err
+			);
 
-				return Box::pin(future::ready(Ok(())));
-			},
-		};
+			err
+		});
 
 		let slot_remaining_duration = self.slot_remaining_duration(&slot_info);
 		let proposing_remaining_duration = self.proposing_remaining_duration(&chain_head, &slot_info);
 		let logs = self.pre_digest_data(slot_number, &claim);
 
 		// deadline our production to approx. the end of the slot
-		let proposing = proposer.propose(
+		let proposing = awaiting_proposer.and_then(move |mut proposer| proposer.propose(
 			slot_info.inherent_data,
 			sp_runtime::generic::Digest {
 				logs,
 			},
 			slot_remaining_duration,
 			RecordProof::No,
-		).map_err(|e| sp_consensus::Error::ClientImport(format!("{:?}", e)));
+		).map_err(|e| sp_consensus::Error::ClientImport(format!("{:?}", e))));
+
 		let delay: Box<dyn Future<Output=()> + Unpin + Send> = match proposing_remaining_duration {
 			Some(r) => Box::new(Delay::new(r)),
 			None => Box::new(future::pending()),
diff --git a/client/db/Cargo.toml b/client/db/Cargo.toml
index d34b04a17edd3..dcc7df29ca11c 100644
--- a/client/db/Cargo.toml
+++ b/client/db/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "sc-client-db"
-version = "2.0.0"
+version = "0.8.0"
 authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2018"
 
@@ -18,10 +18,10 @@ codec = { package = "parity-scale-codec", version = "1.0.0", features = ["derive
 sc-client-api = { version = "2.0.0", path = "../api" }
 sp-core = { version = "2.0.0", path = "../../primitives/core" }
 sp-runtime = { version = "2.0.0", path = "../../primitives/runtime" }
-sc-client = { version = "2.0.0", path = "../" }
-sp-state-machine = { version = "2.0.0", path = "../../primitives/state-machine" }
-sc-executor = { version = "2.0.0", path = "../executor" }
-sc-state-db = { version = "2.0.0", path = "../state-db" }
+sc-client = { version = "0.8", path = "../" }
+sp-state-machine = { version = "0.8", path = "../../primitives/state-machine" }
+sc-executor = { version = "0.8", path = "../executor" }
+sc-state-db = { version = "0.8", path = "../state-db" }
 sp-trie = { version = "2.0.0", path = "../../primitives/trie" }
 sp-consensus = { version = "0.8", path = "../../primitives/consensus/common" }
 sp-blockchain = { version = "2.0.0", path = "../../primitives/blockchain" }
@@ -31,6 +31,8 @@ sp-keyring = { version = "2.0.0", path = "../../primitives/keyring" }
 substrate-test-runtime-client = { version = "2.0.0", path = "../../test-utils/runtime/client" }
 env_logger = "0.7.0"
 quickcheck = "0.9"
+kvdb-rocksdb = "0.4"
+tempdir = "0.3"
 
 [features]
 default = []
diff --git a/client/db/src/cache/list_cache.rs b/client/db/src/cache/list_cache.rs
index 6345486f17f94..72278a1e85e6d 100644
--- a/client/db/src/cache/list_cache.rs
+++ b/client/db/src/cache/list_cache.rs
@@ -94,6 +94,12 @@ pub enum CommitOperation<Block: BlockT, T: CacheItemT> {
 	BlockReverted(BTreeMap<usize, Option<Fork<Block, T>>>),
 }
 
+/// A set of commit operations.
+#[derive(Debug)]
+pub struct CommitOperations<Block: BlockT, T: CacheItemT> {
+	operations: Vec<CommitOperation<Block, T>>,
+}
+
 /// Single fork of list-based cache.
 #[derive(Debug)]
 #[cfg_attr(test, derive(PartialEq))]
@@ -123,21 +129,17 @@ impl<Block: BlockT, T: CacheItemT, S: Storage<Block, T>> ListCache<Block, T, S>
 		storage: S,
 		pruning_strategy: PruningStrategy<NumberFor<Block>>,
 		best_finalized_block: ComplexBlockId<Block>,
-	) -> Self {
+	) -> ClientResult<Self> {
 		let (best_finalized_entry, unfinalized) = storage.read_meta()
-			.and_then(|meta| read_forks(&storage, meta))
-			.unwrap_or_else(|error| {
-				warn!(target: "db", "Unable to initialize list cache: {}. Restarting", error);
-				(None, Vec::new())
-			});
+			.and_then(|meta| read_forks(&storage, meta))?;
 
-		ListCache {
+		Ok(ListCache {
 			storage,
 			pruning_strategy,
 			best_finalized_block,
 			best_finalized_entry,
 			unfinalized,
-		}
+		})
 	}
 
 	/// Get reference to the storage.
@@ -145,6 +147,12 @@ impl<Block: BlockT, T: CacheItemT, S: Storage<Block, T>> ListCache<Block, T, S>
 		&self.storage
 	}
 
+	/// Get unfinalized forks reference.
+	#[cfg(test)]
+	pub fn unfinalized(&self) -> &[Fork<Block, T>] {
+		&self.unfinalized
+	}
+
 	/// Get value valid at block.
 	pub fn value_at_block(
 		&self,
@@ -156,8 +164,8 @@ impl<Block: BlockT, T: CacheItemT, S: Storage<Block, T>> ListCache<Block, T, S>
 
 			// BUT since we're not guaranteeing to provide correct values for forks
 			// behind the finalized block, check if the block is finalized first
-			if !chain::is_finalized_block(&self.storage, at, Bounded::max_value())? {
-				return Ok(None);
+			if !chain::is_finalized_block(&self.storage, &at, Bounded::max_value())? {
+				return Err(ClientError::NotInFinalizedChain);
 			}
 
 			self.best_finalized_entry.as_ref()
@@ -171,11 +179,14 @@ impl<Block: BlockT, T: CacheItemT, S: Storage<Block, T>> ListCache<Block, T, S>
 			// IF there's no matching fork, ensure that this isn't a block from a fork that has forked
 			// behind the best finalized block and search at finalized fork
 
-			match self.find_unfinalized_fork(at)? {
+			match self.find_unfinalized_fork(&at)? {
 				Some(fork) => Some(&fork.head),
 				None => match self.best_finalized_entry.as_ref() {
-					Some(best_finalized_entry) if chain::is_connected_to_block(&self.storage, &best_finalized_entry.valid_from, at)? =>
-						Some(best_finalized_entry),
+					Some(best_finalized_entry) if chain::is_connected_to_block(
+						&self.storage,
+						&at,
+						&best_finalized_entry.valid_from,
+					)? => Some(best_finalized_entry),
 					_ => None,
 				},
 			}
@@ -198,9 +209,98 @@ impl<Block: BlockT, T: CacheItemT, S: Storage<Block, T>> ListCache<Block, T, S>
 		block: ComplexBlockId<Block>,
 		value: Option<T>,
 		entry_type: EntryType,
+		operations: &mut CommitOperations<Block, T>,
+	) -> ClientResult<()> {
+		Ok(operations.append(self.do_on_block_insert(tx, parent, block, value, entry_type, operations)?))
+	}
+
+	/// When previously inserted block is finalized.
+	pub fn on_block_finalize<Tx: StorageTransaction<Block, T>>(
+		&self,
+		tx: &mut Tx,
+		parent: ComplexBlockId<Block>,
+		block: ComplexBlockId<Block>,
+		operations: &mut CommitOperations<Block, T>,
+	) -> ClientResult<()> {
+		Ok(operations.append(self.do_on_block_finalize(tx, parent, block, operations)?))
+	}
+
+	/// When block is reverted.
+	pub fn on_block_revert<Tx: StorageTransaction<Block, T>>(
+		&self,
+		tx: &mut Tx,
+		reverted_block: &ComplexBlockId<Block>,
+		operations: &mut CommitOperations<Block, T>,
+	) -> ClientResult<()> {
+		Ok(operations.append(Some(self.do_on_block_revert(tx, reverted_block)?)))
+	}
+
+	/// When transaction is committed.
+	pub fn on_transaction_commit(&mut self, ops: CommitOperations<Block, T>) {
+		for op in ops.operations {
+			match op {
+				CommitOperation::AppendNewBlock(index, best_block) => {
+					let mut fork = self.unfinalized.get_mut(index)
+						.expect("ListCache is a crate-private type;
+							internal clients of ListCache are committing transaction while cache is locked;
+							CommitOperation holds valid references while cache is locked; qed");
+					fork.best_block = Some(best_block);
+				},
+				CommitOperation::AppendNewEntry(index, entry) => {
+					let mut fork = self.unfinalized.get_mut(index)
+						.expect("ListCache is a crate-private type;
+							internal clients of ListCache are committing transaction while cache is locked;
+							CommitOperation holds valid references while cache is locked; qed");
+					fork.best_block = Some(entry.valid_from.clone());
+					fork.head = entry;
+				},
+				CommitOperation::AddNewFork(entry) => {
+					self.unfinalized.push(Fork {
+						best_block: Some(entry.valid_from.clone()),
+						head: entry,
+					});
+				},
+				CommitOperation::BlockFinalized(block, finalizing_entry, forks) => {
+					self.best_finalized_block = block;
+					if let Some(finalizing_entry) = finalizing_entry {
+						self.best_finalized_entry = Some(finalizing_entry);
+					}
+					for fork_index in forks.iter().rev() {
+						self.unfinalized.remove(*fork_index);
+					}
+				},
+				CommitOperation::BlockReverted(forks) => {
+					for (fork_index, updated_fork) in forks.into_iter().rev() {
+						match updated_fork {
+							Some(updated_fork) => self.unfinalized[fork_index] = updated_fork,
+							None => { self.unfinalized.remove(fork_index); },
+						}
+					}
+				},
+			}
+		}
+	}
+
+	fn do_on_block_insert<Tx: StorageTransaction<Block, T>>(
+		&self,
+		tx: &mut Tx,
+		parent: ComplexBlockId<Block>,
+		block: ComplexBlockId<Block>,
+		value: Option<T>,
+		entry_type: EntryType,
+		operations: &CommitOperations<Block, T>,
 	) -> ClientResult<Option<CommitOperation<Block, T>>> {
 		// this guarantee is currently provided by LightStorage && we're relying on it here
-		debug_assert!(entry_type != EntryType::Final || self.best_finalized_block.hash == parent.hash);
+		let prev_operation = operations.operations.last();
+		debug_assert!(
+			entry_type != EntryType::Final ||
+			self.best_finalized_block.hash == parent.hash ||
+			match prev_operation {
+				Some(&CommitOperation::BlockFinalized(ref best_finalized_block, _, _))
+					=> best_finalized_block.hash == parent.hash,
+				_ => false,
+			}
+		);
 
 		// we do not store any values behind finalized
 		if block.number != Zero::zero() && self.best_finalized_block.number >= block.number {
@@ -296,7 +396,7 @@ impl<Block: BlockT, T: CacheItemT, S: Storage<Block, T>> ListCache<Block, T, S>
 		}
 
 		// cleanup database from abandoned unfinalized forks and obsolete finalized entries
-		let abandoned_forks = self.destroy_abandoned_forks(tx, &block);
+		let abandoned_forks = self.destroy_abandoned_forks(tx, &block, prev_operation);
 		self.prune_finalized_entries(tx, &block);
 
 		match new_storage_entry {
@@ -310,34 +410,39 @@ impl<Block: BlockT, T: CacheItemT, S: Storage<Block, T>> ListCache<Block, T, S>
 		}
 	}
 
-	/// When previously inserted block is finalized.
-	pub fn on_block_finalize<Tx: StorageTransaction<Block, T>>(
+	fn do_on_block_finalize<Tx: StorageTransaction<Block, T>>(
 		&self,
 		tx: &mut Tx,
 		parent: ComplexBlockId<Block>,
 		block: ComplexBlockId<Block>,
+		operations: &CommitOperations<Block, T>,
 	) -> ClientResult<Option<CommitOperation<Block, T>>> {
-		// this guarantee is currently provided by LightStorage && we're relying on it here
-		debug_assert_eq!(self.best_finalized_block.hash, parent.hash);
+		// this guarantee is currently provided by db backend && we're relying on it here
+		let prev_operation = operations.operations.last();
+		debug_assert!(
+			self.best_finalized_block.hash == parent.hash ||
+			match prev_operation {
+				Some(&CommitOperation::BlockFinalized(ref best_finalized_block, _, _))
+					=> best_finalized_block.hash == parent.hash,
+				_ => false,
+			}
+		);
 
 		// there could be at most one entry that is finalizing
 		let finalizing_entry = self.storage.read_entry(&block)?
 			.map(|entry| entry.into_entry(block.clone()));
 
 		// cleanup database from abandoned unfinalized forks and obsolete finalized entries
-		let abandoned_forks = self.destroy_abandoned_forks(tx, &block);
+		let abandoned_forks = self.destroy_abandoned_forks(tx, &block, prev_operation);
 		self.prune_finalized_entries(tx, &block);
 
-		let update_meta = finalizing_entry.is_some();
 		let operation = CommitOperation::BlockFinalized(block, finalizing_entry, abandoned_forks);
-		if update_meta {
-			tx.update_meta(self.best_finalized_entry.as_ref(), &self.unfinalized, &operation);
-		}
+		tx.update_meta(self.best_finalized_entry.as_ref(), &self.unfinalized, &operation);
+
 		Ok(Some(operation))
 	}
 
-	/// When block is reverted.
-	pub fn on_block_revert<Tx: StorageTransaction<Block, T>>(
+	fn do_on_block_revert<Tx: StorageTransaction<Block, T>>(
 		&self,
 		tx: &mut Tx,
 		reverted_block: &ComplexBlockId<Block>,
@@ -374,50 +479,6 @@ impl<Block: BlockT, T: CacheItemT, S: Storage<Block, T>> ListCache<Block, T, S>
 		Ok(operation)
 	}
 
-	/// When transaction is committed.
-	pub fn on_transaction_commit(&mut self, op: CommitOperation<Block, T>) {
-		match op {
-			CommitOperation::AppendNewBlock(index, best_block) => {
-				let mut fork = self.unfinalized.get_mut(index)
-					.expect("ListCache is a crate-private type;
-						internal clients of ListCache are committing transaction while cache is locked;
-						CommitOperation holds valid references while cache is locked; qed");
-				fork.best_block = Some(best_block);
-			},
-			CommitOperation::AppendNewEntry(index, entry) => {
-				let mut fork = self.unfinalized.get_mut(index)
-					.expect("ListCache is a crate-private type;
-						internal clients of ListCache are committing transaction while cache is locked;
-						CommitOperation holds valid references while cache is locked; qed");
-				fork.best_block = Some(entry.valid_from.clone());
-				fork.head = entry;
-			},
-			CommitOperation::AddNewFork(entry) => {
-				self.unfinalized.push(Fork {
-					best_block: Some(entry.valid_from.clone()),
-					head: entry,
-				});
-			},
-			CommitOperation::BlockFinalized(block, finalizing_entry, forks) => {
-				self.best_finalized_block = block;
-				if let Some(finalizing_entry) = finalizing_entry {
-					self.best_finalized_entry = Some(finalizing_entry);
-				}
-				for fork_index in forks.iter().rev() {
-					self.unfinalized.remove(*fork_index);
-				}
-			},
-			CommitOperation::BlockReverted(forks) => {
-				for (fork_index, updated_fork) in forks.into_iter().rev() {
-					match updated_fork {
-						Some(updated_fork) => self.unfinalized[fork_index] = updated_fork,
-						None => { self.unfinalized.remove(fork_index); },
-					}
-				}
-			},
-		}
-	}
-
 	/// Prune old finalized entries.
 	fn prune_finalized_entries<Tx: StorageTransaction<Block, T>>(
 		&self,
@@ -475,10 +536,22 @@ impl<Block: BlockT, T: CacheItemT, S: Storage<Block, T>> ListCache<Block, T, S>
 	fn destroy_abandoned_forks<Tx: StorageTransaction<Block, T>>(
 		&self,
 		tx: &mut Tx,
-		block: &ComplexBlockId<Block>
+		block: &ComplexBlockId<Block>,
+		prev_operation: Option<&CommitOperation<Block, T>>,
 	) -> BTreeSet<usize> {
-		let mut destroyed = BTreeSet::new();
-		for (index, fork) in self.unfinalized.iter().enumerate() {
+		// if some block has been finalized already => take it into account
+		let prev_abandoned_forks = match prev_operation {
+			Some(&CommitOperation::BlockFinalized(_, _, ref abandoned_forks)) => Some(abandoned_forks),
+			_ => None,
+		};
+
+		let mut destroyed = prev_abandoned_forks.cloned().unwrap_or_else(|| BTreeSet::new());
+		let live_unfinalized = self.unfinalized.iter()
+			.enumerate()
+			.filter(|(idx, _)| prev_abandoned_forks
+				.map(|prev_abandoned_forks| !prev_abandoned_forks.contains(idx))
+				.unwrap_or(true));
+		for (index, fork) in live_unfinalized {
 			if fork.head.valid_from.number == block.number {
 				destroyed.insert(index);
 				if fork.head.valid_from.hash != block.hash {
@@ -493,7 +566,10 @@ impl<Block: BlockT, T: CacheItemT, S: Storage<Block, T>> ListCache<Block, T, S>
 	}
 
 	/// Search unfinalized fork where given block belongs.
-	fn find_unfinalized_fork(&self, block: &ComplexBlockId<Block>) -> ClientResult<Option<&Fork<Block, T>>> {
+	fn find_unfinalized_fork(
+		&self,
+		block: &ComplexBlockId<Block>,
+	) -> ClientResult<Option<&Fork<Block, T>>> {
 		for unfinalized in &self.unfinalized {
 			if unfinalized.matches(&self.storage, block)? {
 				return Ok(Some(&unfinalized));
@@ -549,7 +625,7 @@ impl<Block: BlockT, T: CacheItemT> Fork<Block, T> {
 		};
 
 		// check if the parent is connected to the beginning of the range
-		if !chain::is_connected_to_block(storage, &parent, &begin)? {
+		if !chain::is_connected_to_block(storage, parent, &begin)? {
 			return Ok(None);
 		}
 
@@ -621,6 +697,65 @@ impl<Block: BlockT, T: CacheItemT> Fork<Block, T> {
 	}
 }
 
+impl<Block: BlockT, T: CacheItemT> Default for CommitOperations<Block, T> {
+	fn default() -> Self {
+		CommitOperations { operations: Vec::new() }
+	}
+}
+
+// This should never be allowed for non-test code to avoid revealing its internals.
+#[cfg(test)]
+impl<Block: BlockT, T: CacheItemT> From<Vec<CommitOperation<Block, T>>> for CommitOperations<Block, T> {
+	fn from(operations: Vec<CommitOperation<Block, T>>) -> Self {
+		CommitOperations { operations }
+	}
+}
+
+impl<Block: BlockT, T: CacheItemT> CommitOperations<Block, T> {
+	/// Append operation to the set.
+	fn append(&mut self, new_operation: Option<CommitOperation<Block, T>>) {
+		let new_operation = match new_operation {
+			Some(new_operation) => new_operation,
+			None => return,
+		};
+
+		let last_operation = match self.operations.pop() {
+			Some(last_operation) => last_operation,
+			None => {
+				self.operations.push(new_operation);
+				return;
+			},
+		};
+
+		// we are able (and obliged to) to merge two consequent block finalization operations
+		match last_operation {
+			CommitOperation::BlockFinalized(old_finalized_block, old_finalized_entry, old_abandoned_forks) => {
+				match new_operation {
+					CommitOperation::BlockFinalized(new_finalized_block, new_finalized_entry, new_abandoned_forks) => {
+						self.operations.push(CommitOperation::BlockFinalized(
+							new_finalized_block,
+							new_finalized_entry,
+							new_abandoned_forks,
+						));
+					},
+					_ => {
+						self.operations.push(CommitOperation::BlockFinalized(
+							old_finalized_block,
+							old_finalized_entry,
+							old_abandoned_forks,
+						));
+						self.operations.push(new_operation);
+					},
+				}
+			},
+			_ => {
+				self.operations.push(last_operation);
+				self.operations.push(new_operation);
+			},
+		}
+	}
+}
+
 /// Destroy fork by deleting all unfinalized entries.
 pub fn destroy_fork<Block: BlockT, T: CacheItemT, S: Storage<Block, T>, Tx: StorageTransaction<Block, T>>(
 	head_valid_from: ComplexBlockId<Block>,
@@ -674,7 +809,7 @@ mod chain {
 		block1: &ComplexBlockId<Block>,
 		block2: &ComplexBlockId<Block>,
 	) -> ClientResult<bool> {
-		let (begin, end) = if block1 > block2 { (block2, block1) } else { (block1, block2) };
+		let (begin, end) = if *block1 > *block2 { (block2, block1) } else { (block1, block2) };
 		let mut current = storage.read_header(&end.hash)?
 			.ok_or_else(|| ClientError::UnknownBlock(format!("{}", end.hash)))?;
 		while *current.number() > begin.number {
@@ -773,8 +908,8 @@ pub mod tests {
 		// when block is earlier than best finalized block AND it is not finalized
 		// --- 50 ---
 		// ----------> [100]
-		assert_eq!(ListCache::<_, u64, _>::new(DummyStorage::new(), PruningStrategy::ByDepth(1024), test_id(100))
-			.value_at_block(&test_id(50)).unwrap(), None);
+		assert!(ListCache::<_, u64, _>::new(DummyStorage::new(), PruningStrategy::ByDepth(1024), test_id(100))
+			.unwrap().value_at_block(&test_id(50)).is_err());
 		// when block is earlier than best finalized block AND it is finalized AND value is some
 		// [30] ---- 50 ---> [100]
 		assert_eq!(ListCache::new(
@@ -784,7 +919,7 @@ pub mod tests {
 				.with_entry(test_id(100), StorageEntry { prev_valid_from: Some(test_id(30)), value: 100 })
 				.with_entry(test_id(30), StorageEntry { prev_valid_from: None, value: 30 }),
 			PruningStrategy::ByDepth(1024), test_id(100)
-		).value_at_block(&test_id(50)).unwrap(), Some((test_id(30), Some(test_id(100)), 30)));
+		).unwrap().value_at_block(&test_id(50)).unwrap(), Some((test_id(30), Some(test_id(100)), 30)));
 		// when block is the best finalized block AND value is some
 		// ---> [100]
 		assert_eq!(ListCache::new(
@@ -794,18 +929,18 @@ pub mod tests {
 				.with_entry(test_id(100), StorageEntry { prev_valid_from: Some(test_id(30)), value: 100 })
 				.with_entry(test_id(30), StorageEntry { prev_valid_from: None, value: 30 }),
 			PruningStrategy::ByDepth(1024), test_id(100)
-		).value_at_block(&test_id(100)).unwrap(), Some((test_id(100), None, 100)));
+		).unwrap().value_at_block(&test_id(100)).unwrap(), Some((test_id(100), None, 100)));
 		// when block is parallel to the best finalized block
 		// ---- 100
 		// ---> [100]
-		assert_eq!(ListCache::new(
+		assert!(ListCache::new(
 			DummyStorage::new()
 				.with_meta(Some(test_id(100)), Vec::new())
 				.with_id(50, H256::from_low_u64_be(50))
 				.with_entry(test_id(100), StorageEntry { prev_valid_from: Some(test_id(30)), value: 100 })
 				.with_entry(test_id(30), StorageEntry { prev_valid_from: None, value: 30 }),
 			PruningStrategy::ByDepth(1024), test_id(100)
-		).value_at_block(&ComplexBlockId::new(H256::from_low_u64_be(2), 100)).unwrap(), None);
+		).unwrap().value_at_block(&ComplexBlockId::new(H256::from_low_u64_be(2), 100)).is_err());
 
 		// when block is later than last finalized block AND there are no forks AND finalized value is Some
 		// ---> [100] --- 200
@@ -815,7 +950,7 @@ pub mod tests {
 				.with_id(50, H256::from_low_u64_be(50))
 				.with_entry(test_id(100), StorageEntry { prev_valid_from: Some(test_id(30)), value: 100 }),
 			PruningStrategy::ByDepth(1024), test_id(100)
-		).value_at_block(&test_id(200)).unwrap(), Some((test_id(100), None, 100)));
+		).unwrap().value_at_block(&test_id(200)).unwrap(), Some((test_id(100), None, 100)));
 
 		// when block is later than last finalized block AND there are no matching forks
 		// AND block is connected to finalized block AND finalized value is Some
@@ -831,7 +966,7 @@ pub mod tests {
 				.with_header(test_header(4))
 				.with_header(fork_header(0, 2, 3)),
 			PruningStrategy::ByDepth(1024), test_id(2)
-		).value_at_block(&fork_id(0, 2, 3)).unwrap(), Some((correct_id(2), None, 2)));
+		).unwrap().value_at_block(&fork_id(0, 2, 3)).unwrap(), Some((correct_id(2), None, 2)));
 		// when block is later than last finalized block AND there are no matching forks
 		// AND block is not connected to finalized block
 		//    ---   2  --- 3
@@ -848,7 +983,7 @@ pub mod tests {
 				.with_header(fork_header(0, 1, 3))
 				.with_header(fork_header(0, 1, 2)),
 			PruningStrategy::ByDepth(1024), test_id(2)
-		).value_at_block(&fork_id(0, 1, 3)).unwrap(), None);
+		).unwrap().value_at_block(&fork_id(0, 1, 3)).unwrap(), None);
 
 		// when block is later than last finalized block AND it appends to unfinalized fork from the end
 		// AND unfinalized value is Some
@@ -861,7 +996,7 @@ pub mod tests {
 				.with_header(test_header(4))
 				.with_header(test_header(5)),
 			PruningStrategy::ByDepth(1024), test_id(2)
-		).value_at_block(&correct_id(5)).unwrap(), Some((correct_id(4), None, 4)));
+		).unwrap().value_at_block(&correct_id(5)).unwrap(), Some((correct_id(4), None, 4)));
 		// when block is later than last finalized block AND it does not fits unfinalized fork
 		// AND it is connected to the finalized block AND finalized value is Some
 		// ---> [2] ----------> [4]
@@ -876,7 +1011,7 @@ pub mod tests {
 				.with_header(test_header(4))
 				.with_header(fork_header(0, 2, 3)),
 			PruningStrategy::ByDepth(1024), test_id(2)
-		).value_at_block(&fork_id(0, 2, 3)).unwrap(), Some((correct_id(2), None, 2)));
+		).unwrap().value_at_block(&fork_id(0, 2, 3)).unwrap(), Some((correct_id(2), None, 2)));
 	}
 
 	#[test]
@@ -885,22 +1020,25 @@ pub mod tests {
 		let fin = EntryType::Final;
 
 		// when trying to insert block < finalized number
-		assert!(ListCache::new(DummyStorage::new(), PruningStrategy::ByDepth(1024), test_id(100))
-			.on_block_insert(
+		let mut ops = Default::default();
+		assert!(ListCache::new(DummyStorage::new(), PruningStrategy::ByDepth(1024), test_id(100)).unwrap()
+			.do_on_block_insert(
 				&mut DummyTransaction::new(),
 				test_id(49),
 				test_id(50),
 				Some(50),
 				nfin,
+				&mut ops,
 			).unwrap().is_none());
 		// when trying to insert block @ finalized number
-		assert!(ListCache::new(DummyStorage::new(), PruningStrategy::ByDepth(1024), test_id(100))
-			.on_block_insert(
+		assert!(ListCache::new(DummyStorage::new(), PruningStrategy::ByDepth(1024), test_id(100)).unwrap()
+			.do_on_block_insert(
 				&mut DummyTransaction::new(),
 				test_id(99),
 				test_id(100),
 				Some(100),
 				nfin,
+				&Default::default(),
 			).unwrap().is_none());
 
 		// when trying to insert non-final block AND it appends to the best block of unfinalized fork
@@ -910,19 +1048,23 @@ pub mod tests {
 				.with_meta(None, vec![test_id(4)])
 				.with_entry(test_id(4), StorageEntry { prev_valid_from: None, value: 4 }),
 			PruningStrategy::ByDepth(1024), test_id(2)
-		);
+		).unwrap();
 		cache.unfinalized[0].best_block = Some(test_id(4));
 		let mut tx = DummyTransaction::new();
-		assert_eq!(cache.on_block_insert(&mut tx, test_id(4), test_id(5), Some(4), nfin).unwrap(),
-			Some(CommitOperation::AppendNewBlock(0, test_id(5))));
+		assert_eq!(
+			cache.do_on_block_insert(&mut tx, test_id(4), test_id(5), Some(4), nfin, &Default::default()).unwrap(),
+			Some(CommitOperation::AppendNewBlock(0, test_id(5))),
+		);
 		assert!(tx.inserted_entries().is_empty());
 		assert!(tx.removed_entries().is_empty());
 		assert!(tx.updated_meta().is_none());
 		// when trying to insert non-final block AND it appends to the best block of unfinalized fork
 		// AND new value is the same as in the fork' best block
 		let mut tx = DummyTransaction::new();
-		assert_eq!(cache.on_block_insert(&mut tx, test_id(4), test_id(5), Some(5), nfin).unwrap(),
-			Some(CommitOperation::AppendNewEntry(0, Entry { valid_from: test_id(5), value: 5 })));
+		assert_eq!(
+			cache.do_on_block_insert(&mut tx, test_id(4), test_id(5), Some(5), nfin, &Default::default()).unwrap(),
+			Some(CommitOperation::AppendNewEntry(0, Entry { valid_from: test_id(5), value: 5 })),
+		);
 		assert_eq!(*tx.inserted_entries(), vec![test_id(5).hash].into_iter().collect());
 		assert!(tx.removed_entries().is_empty());
 		assert_eq!(*tx.updated_meta(), Some(Metadata { finalized: None, unfinalized: vec![test_id(5)] }));
@@ -935,18 +1077,36 @@ pub mod tests {
 				.with_entry(correct_id(4), StorageEntry { prev_valid_from: None, value: 4 })
 				.with_header(test_header(4)),
 			PruningStrategy::ByDepth(1024), test_id(2)
-		);
+		).unwrap();
 		let mut tx = DummyTransaction::new();
-		assert_eq!(cache.on_block_insert(&mut tx, correct_id(4), correct_id(5), Some(4), nfin).unwrap(),
-			Some(CommitOperation::AppendNewBlock(0, correct_id(5))));
+		assert_eq!(
+			cache.do_on_block_insert(
+				&mut tx,
+				correct_id(4),
+				correct_id(5),
+				Some(4),
+				nfin,
+				&Default::default(),
+			).unwrap(),
+			Some(CommitOperation::AppendNewBlock(0, correct_id(5))),
+		);
 		assert!(tx.inserted_entries().is_empty());
 		assert!(tx.removed_entries().is_empty());
 		assert!(tx.updated_meta().is_none());
 		// when trying to insert non-final block AND it is the first block that appends to the best block of unfinalized fork
 		// AND new value is the same as in the fork' best block
 		let mut tx = DummyTransaction::new();
-		assert_eq!(cache.on_block_insert(&mut tx, correct_id(4), correct_id(5), Some(5), nfin).unwrap(),
-			Some(CommitOperation::AppendNewEntry(0, Entry { valid_from: correct_id(5), value: 5 })));
+		assert_eq!(
+			cache.do_on_block_insert(
+				&mut tx,
+				correct_id(4),
+				correct_id(5),
+				Some(5),
+				nfin,
+				&Default::default(),
+			).unwrap(),
+			Some(CommitOperation::AppendNewEntry(0, Entry { valid_from: correct_id(5), value: 5 })),
+		);
 		assert_eq!(*tx.inserted_entries(), vec![correct_id(5).hash].into_iter().collect());
 		assert!(tx.removed_entries().is_empty());
 		assert_eq!(*tx.updated_meta(), Some(Metadata { finalized: None, unfinalized: vec![correct_id(5)] }));
@@ -961,10 +1121,13 @@ pub mod tests {
 				.with_header(test_header(3))
 				.with_header(test_header(4)),
 			PruningStrategy::ByDepth(1024), correct_id(2)
-		);
+		).unwrap();
 		let mut tx = DummyTransaction::new();
-		assert_eq!(cache.on_block_insert(&mut tx, correct_id(3), fork_id(0, 3, 4), Some(14), nfin).unwrap(),
-			Some(CommitOperation::AddNewFork(Entry { valid_from: fork_id(0, 3, 4), value: 14 })));
+		assert_eq!(
+			cache.do_on_block_insert(&mut tx, correct_id(3), fork_id(0, 3, 4), Some(14), nfin, &Default::default())
+				.unwrap(),
+			Some(CommitOperation::AddNewFork(Entry { valid_from: fork_id(0, 3, 4), value: 14 })),
+		);
 		assert_eq!(*tx.inserted_entries(), vec![fork_id(0, 3, 4).hash].into_iter().collect());
 		assert!(tx.removed_entries().is_empty());
 		assert_eq!(*tx.updated_meta(), Some(Metadata { finalized: Some(correct_id(2)), unfinalized: vec![correct_id(4), fork_id(0, 3, 4)] }));
@@ -976,9 +1139,13 @@ pub mod tests {
 				.with_meta(Some(correct_id(2)), vec![])
 				.with_entry(correct_id(2), StorageEntry { prev_valid_from: None, value: 2 }),
 			PruningStrategy::ByDepth(1024), correct_id(2)
-		);
+		).unwrap();
 		let mut tx = DummyTransaction::new();
-		assert_eq!(cache.on_block_insert(&mut tx, correct_id(2), correct_id(3), Some(2), nfin).unwrap(), None);
+		assert_eq!(
+			cache.do_on_block_insert(&mut tx, correct_id(2), correct_id(3), Some(2), nfin, &Default::default())
+				.unwrap(),
+			None,
+		);
 		assert!(tx.inserted_entries().is_empty());
 		assert!(tx.removed_entries().is_empty());
 		assert!(tx.updated_meta().is_none());
@@ -989,19 +1156,23 @@ pub mod tests {
 				.with_meta(Some(correct_id(2)), vec![])
 				.with_entry(correct_id(2), StorageEntry { prev_valid_from: None, value: 2 }),
 			PruningStrategy::ByDepth(1024), correct_id(2)
-		);
+		).unwrap();
 		let mut tx = DummyTransaction::new();
-		assert_eq!(cache.on_block_insert(&mut tx, correct_id(2), correct_id(3), Some(3), nfin).unwrap(),
-			Some(CommitOperation::AddNewFork(Entry { valid_from: correct_id(3), value: 3 })));
+		assert_eq!(
+			cache.do_on_block_insert(&mut tx, correct_id(2), correct_id(3), Some(3), nfin, &Default::default())
+				.unwrap(),
+			Some(CommitOperation::AddNewFork(Entry { valid_from: correct_id(3), value: 3 })),
+		);
 		assert_eq!(*tx.inserted_entries(), vec![correct_id(3).hash].into_iter().collect());
 		assert!(tx.removed_entries().is_empty());
 		assert_eq!(*tx.updated_meta(), Some(Metadata { finalized: Some(correct_id(2)), unfinalized: vec![correct_id(3)] }));
 
 		// when inserting finalized entry AND there are no previous finalized entries
-		let cache = ListCache::new(DummyStorage::new(), PruningStrategy::ByDepth(1024), correct_id(2));
+		let cache = ListCache::new(DummyStorage::new(), PruningStrategy::ByDepth(1024), correct_id(2)).unwrap();
 		let mut tx = DummyTransaction::new();
 		assert_eq!(
-			cache.on_block_insert(&mut tx, correct_id(2), correct_id(3), Some(3), fin).unwrap(),
+			cache.do_on_block_insert(&mut tx, correct_id(2), correct_id(3), Some(3), fin, &Default::default())
+				.unwrap(),
 			Some(CommitOperation::BlockFinalized(
 				correct_id(3),
 				Some(Entry { valid_from: correct_id(3), value: 3 }),
@@ -1017,17 +1188,19 @@ pub mod tests {
 				.with_meta(Some(correct_id(2)), vec![])
 				.with_entry(correct_id(2), StorageEntry { prev_valid_from: None, value: 2 }),
 			PruningStrategy::ByDepth(1024), correct_id(2)
-		);
+		).unwrap();
 		let mut tx = DummyTransaction::new();
-		assert_eq!(cache.on_block_insert(&mut tx, correct_id(2), correct_id(3), Some(2), fin).unwrap(),
-			Some(CommitOperation::BlockFinalized(correct_id(3), None, Default::default())));
+		assert_eq!(
+			cache.do_on_block_insert(&mut tx, correct_id(2), correct_id(3), Some(2), fin, &Default::default()).unwrap(),
+			Some(CommitOperation::BlockFinalized(correct_id(3), None, Default::default())),
+		);
 		assert!(tx.inserted_entries().is_empty());
 		assert!(tx.removed_entries().is_empty());
 		assert!(tx.updated_meta().is_none());
 		// when inserting finalized entry AND value differs from previous finalized
 		let mut tx = DummyTransaction::new();
 		assert_eq!(
-			cache.on_block_insert(&mut tx, correct_id(2), correct_id(3), Some(3), fin).unwrap(),
+			cache.do_on_block_insert(&mut tx, correct_id(2), correct_id(3), Some(3), fin, &Default::default()).unwrap(),
 			Some(CommitOperation::BlockFinalized(
 				correct_id(3),
 				Some(Entry { valid_from: correct_id(3), value: 3 }),
@@ -1045,10 +1218,12 @@ pub mod tests {
 				.with_entry(correct_id(2), StorageEntry { prev_valid_from: None, value: 2 })
 				.with_entry(fork_id(0, 1, 3), StorageEntry { prev_valid_from: None, value: 13 }),
 			PruningStrategy::ByDepth(1024), correct_id(2)
-		);
+		).unwrap();
 		let mut tx = DummyTransaction::new();
-		assert_eq!(cache.on_block_insert(&mut tx, correct_id(2), correct_id(3), Some(2), fin).unwrap(),
-			Some(CommitOperation::BlockFinalized(correct_id(3), None, vec![0].into_iter().collect())));
+		assert_eq!(
+			cache.do_on_block_insert(&mut tx, correct_id(2), correct_id(3), Some(2), fin, &Default::default()).unwrap(),
+			Some(CommitOperation::BlockFinalized(correct_id(3), None, vec![0].into_iter().collect())),
+		);
 	}
 
 	#[test]
@@ -1060,13 +1235,18 @@ pub mod tests {
 				.with_entry(correct_id(2), StorageEntry { prev_valid_from: None, value: 2 })
 				.with_entry(correct_id(5), StorageEntry { prev_valid_from: Some(correct_id(2)), value: 5 }),
 			PruningStrategy::ByDepth(1024), correct_id(2)
-		);
+		).unwrap();
 		let mut tx = DummyTransaction::new();
-		assert_eq!(cache.on_block_finalize(&mut tx, correct_id(2), correct_id(3)).unwrap(),
-			Some(CommitOperation::BlockFinalized(correct_id(3), None, Default::default())));
+		assert_eq!(
+			cache.do_on_block_finalize(&mut tx, correct_id(2), correct_id(3), &Default::default()).unwrap(),
+			Some(CommitOperation::BlockFinalized(correct_id(3), None, Default::default())),
+		);
 		assert!(tx.inserted_entries().is_empty());
 		assert!(tx.removed_entries().is_empty());
-		assert!(tx.updated_meta().is_none());
+		assert_eq!(
+			*tx.updated_meta(),
+			Some(Metadata { finalized: Some(correct_id(2)), unfinalized: vec![correct_id(5)] }),
+		);
 		// finalization finalizes entry
 		let cache = ListCache::new(
 			DummyStorage::new()
@@ -1074,10 +1254,10 @@ pub mod tests {
 				.with_entry(correct_id(2), StorageEntry { prev_valid_from: None, value: 2 })
 				.with_entry(correct_id(5), StorageEntry { prev_valid_from: Some(correct_id(2)), value: 5 }),
 			PruningStrategy::ByDepth(1024), correct_id(4)
-		);
+		).unwrap();
 		let mut tx = DummyTransaction::new();
 		assert_eq!(
-			cache.on_block_finalize(&mut tx, correct_id(4), correct_id(5)).unwrap(),
+			cache.do_on_block_finalize(&mut tx, correct_id(4), correct_id(5), &Default::default()).unwrap(),
 			Some(CommitOperation::BlockFinalized(
 				correct_id(5),
 				Some(Entry { valid_from: correct_id(5), value: 5 }),
@@ -1094,10 +1274,12 @@ pub mod tests {
 				.with_entry(correct_id(2), StorageEntry { prev_valid_from: None, value: 2 })
 				.with_entry(fork_id(0, 1, 3), StorageEntry { prev_valid_from: None, value: 13 }),
 			PruningStrategy::ByDepth(1024), correct_id(2)
-		);
+		).unwrap();
 		let mut tx = DummyTransaction::new();
-		assert_eq!(cache.on_block_finalize(&mut tx, correct_id(2), correct_id(3)).unwrap(),
-			Some(CommitOperation::BlockFinalized(correct_id(3), None, vec![0].into_iter().collect())));
+		assert_eq!(
+			cache.do_on_block_finalize(&mut tx, correct_id(2), correct_id(3), &Default::default()).unwrap(),
+			Some(CommitOperation::BlockFinalized(correct_id(3), None, vec![0].into_iter().collect())),
+		);
 	}
 
 	#[test]
@@ -1109,25 +1291,29 @@ pub mod tests {
 				.with_entry(correct_id(5), StorageEntry { prev_valid_from: Some(correct_id(2)), value: 5 })
 				.with_entry(correct_id(6), StorageEntry { prev_valid_from: Some(correct_id(5)), value: 6 }),
 			PruningStrategy::ByDepth(1024), correct_id(2)
-		);
+		).unwrap();
 
 		// when new block is appended to unfinalized fork
-		cache.on_transaction_commit(CommitOperation::AppendNewBlock(0, correct_id(6)));
+		cache.on_transaction_commit(vec![CommitOperation::AppendNewBlock(0, correct_id(6))].into());
 		assert_eq!(cache.unfinalized[0].best_block, Some(correct_id(6)));
 		// when new entry is appended to unfinalized fork
-		cache.on_transaction_commit(CommitOperation::AppendNewEntry(0, Entry { valid_from: correct_id(7), value: 7 }));
+		cache.on_transaction_commit(vec![
+			CommitOperation::AppendNewEntry(0, Entry { valid_from: correct_id(7), value: 7 }),
+		].into());
 		assert_eq!(cache.unfinalized[0].best_block, Some(correct_id(7)));
 		assert_eq!(cache.unfinalized[0].head, Entry { valid_from: correct_id(7), value: 7 });
 		// when new fork is added
-		cache.on_transaction_commit(CommitOperation::AddNewFork(Entry { valid_from: correct_id(10), value: 10 }));
+		cache.on_transaction_commit(vec![
+			CommitOperation::AddNewFork(Entry { valid_from: correct_id(10), value: 10 }),
+		].into());
 		assert_eq!(cache.unfinalized[2].best_block, Some(correct_id(10)));
 		assert_eq!(cache.unfinalized[2].head, Entry { valid_from: correct_id(10), value: 10 });
 		// when block is finalized + entry is finalized + unfinalized forks are deleted
-		cache.on_transaction_commit(CommitOperation::BlockFinalized(
+		cache.on_transaction_commit(vec![CommitOperation::BlockFinalized(
 			correct_id(20),
 			Some(Entry { valid_from: correct_id(20), value: 20 }),
 			vec![0, 1, 2].into_iter().collect(),
-		));
+		)].into());
 		assert_eq!(cache.best_finalized_block, correct_id(20));
 		assert_eq!(cache.best_finalized_entry, Some(Entry { valid_from: correct_id(20), value: 20 }));
 		assert!(cache.unfinalized.is_empty());
@@ -1148,7 +1334,7 @@ pub mod tests {
 				.with_header(test_header(4))
 				.with_header(test_header(5)),
 			PruningStrategy::ByDepth(1024), correct_id(0)
-		).find_unfinalized_fork(&correct_id(4)).unwrap().unwrap().head.valid_from, correct_id(5));
+		).unwrap().find_unfinalized_fork((&correct_id(4)).into()).unwrap().unwrap().head.valid_from, correct_id(5));
 		// --- [2] ---------------> [5]
 		// ----------> [3] ---> 4
 		assert_eq!(ListCache::new(
@@ -1165,7 +1351,8 @@ pub mod tests {
 				.with_header(fork_header(0, 1, 3))
 				.with_header(fork_header(0, 1, 4)),
 			PruningStrategy::ByDepth(1024), correct_id(0)
-		).find_unfinalized_fork(&fork_id(0, 1, 4)).unwrap().unwrap().head.valid_from, fork_id(0, 1, 3));
+		).unwrap()
+			.find_unfinalized_fork((&fork_id(0, 1, 4)).into()).unwrap().unwrap().head.valid_from, fork_id(0, 1, 3));
 		// --- [2] ---------------> [5]
 		// ----------> [3]
 		// -----------------> 4
@@ -1185,7 +1372,7 @@ pub mod tests {
 				.with_header(fork_header(1, 1, 3))
 				.with_header(fork_header(1, 1, 4)),
 			PruningStrategy::ByDepth(1024), correct_id(0)
-		).find_unfinalized_fork(&fork_id(1, 1, 4)).unwrap().is_none());
+		).unwrap().find_unfinalized_fork((&fork_id(1, 1, 4)).into()).unwrap().is_none());
 	}
 
 	#[test]
@@ -1195,7 +1382,7 @@ pub mod tests {
 			.with_entry(test_id(100), StorageEntry { prev_valid_from: Some(test_id(50)), value: 100 })
 			.with_entry(test_id(50), StorageEntry { prev_valid_from: None, value: 50 });
 		assert_eq!(Fork::<_, u64> { best_block: None, head: Entry { valid_from: test_id(100), value: 0 } }
-			.matches(&storage, &test_id(20)).unwrap(), false);
+			.matches(&storage, (&test_id(20)).into()).unwrap(), false);
 		// when block is not connected to the begin block
 		let storage = DummyStorage::new()
 			.with_entry(correct_id(5), StorageEntry { prev_valid_from: Some(correct_id(3)), value: 100 })
@@ -1206,7 +1393,7 @@ pub mod tests {
 			.with_header(fork_header(0, 2, 4))
 			.with_header(fork_header(0, 2, 3));
 		assert_eq!(Fork::<_, u64> { best_block: None, head: Entry { valid_from: correct_id(5), value: 100 } }
-			.matches(&storage, &fork_id(0, 2, 4)).unwrap(), false);
+			.matches(&storage, (&fork_id(0, 2, 4)).into()).unwrap(), false);
 		// when block is not connected to the end block
 		let storage = DummyStorage::new()
 			.with_entry(correct_id(5), StorageEntry { prev_valid_from: Some(correct_id(3)), value: 100 })
@@ -1216,14 +1403,14 @@ pub mod tests {
 			.with_header(test_header(3))
 			.with_header(fork_header(0, 3, 4));
 		assert_eq!(Fork::<_, u64> { best_block: None, head: Entry { valid_from: correct_id(5), value: 100 } }
-			.matches(&storage, &fork_id(0, 3, 4)).unwrap(), false);
+			.matches(&storage, (&fork_id(0, 3, 4)).into()).unwrap(), false);
 		// when block is connected to the begin block AND end is open
 		let storage = DummyStorage::new()
 			.with_entry(correct_id(5), StorageEntry { prev_valid_from: None, value: 100 })
 			.with_header(test_header(5))
 			.with_header(test_header(6));
 		assert_eq!(Fork::<_, u64> { best_block: None, head: Entry { valid_from: correct_id(5), value: 100 } }
-			.matches(&storage, &correct_id(6)).unwrap(), true);
+			.matches(&storage, (&correct_id(6)).into()).unwrap(), true);
 		// when block is connected to the begin block AND to the end block
 		let storage = DummyStorage::new()
 			.with_entry(correct_id(5), StorageEntry { prev_valid_from: Some(correct_id(3)), value: 100 })
@@ -1232,7 +1419,7 @@ pub mod tests {
 			.with_header(test_header(4))
 			.with_header(test_header(3));
 		assert_eq!(Fork::<_, u64> { best_block: None, head: Entry { valid_from: correct_id(5), value: 100 } }
-			.matches(&storage, &correct_id(4)).unwrap(), true);
+			.matches(&storage, (&correct_id(4)).into()).unwrap(), true);
 	}
 
 	#[test]
@@ -1338,9 +1525,21 @@ pub mod tests {
 	#[test]
 	fn is_connected_to_block_fails() {
 		// when storage returns error
-		assert!(chain::is_connected_to_block::<_, u64, _>(&FaultyStorage, &test_id(1), &test_id(100)).is_err());
+		assert!(
+			chain::is_connected_to_block::<_, u64, _>(
+				&FaultyStorage,
+				(&test_id(1)).into(),
+				&test_id(100),
+			).is_err(),
+		);
 		// when there's no header in the storage
-		assert!(chain::is_connected_to_block::<_, u64, _>(&DummyStorage::new(), &test_id(1), &test_id(100)).is_err());
+		assert!(
+			chain::is_connected_to_block::<_, u64, _>(
+				&DummyStorage::new(),
+				(&test_id(1)).into(),
+				&test_id(100),
+			).is_err(),
+		);
 	}
 
 	#[test]
@@ -1348,35 +1547,35 @@ pub mod tests {
 		// when without iterations we end up with different block
 		assert_eq!(chain::is_connected_to_block::<_, u64, _>(&DummyStorage::new()
 			.with_header(test_header(1)),
-			&test_id(1), &correct_id(1)).unwrap(), false);
+			(&test_id(1)).into(), &correct_id(1)).unwrap(), false);
 		// when with ASC iterations we end up with different block
 		assert_eq!(chain::is_connected_to_block::<_, u64, _>(&DummyStorage::new()
 			.with_header(test_header(0))
 			.with_header(test_header(1))
 			.with_header(test_header(2)),
-			&test_id(0), &correct_id(2)).unwrap(), false);
+			(&test_id(0)).into(), &correct_id(2)).unwrap(), false);
 		// when with DESC iterations we end up with different block
 		assert_eq!(chain::is_connected_to_block::<_, u64, _>(&DummyStorage::new()
 			.with_header(test_header(0))
 			.with_header(test_header(1))
 			.with_header(test_header(2)),
-			&correct_id(2), &test_id(0)).unwrap(), false);
+			(&correct_id(2)).into(), &test_id(0)).unwrap(), false);
 		// when without iterations we end up with the same block
 		assert_eq!(chain::is_connected_to_block::<_, u64, _>(&DummyStorage::new()
 			.with_header(test_header(1)),
-			&correct_id(1), &correct_id(1)).unwrap(), true);
+			(&correct_id(1)).into(), &correct_id(1)).unwrap(), true);
 		// when with ASC iterations we end up with the same block
 		assert_eq!(chain::is_connected_to_block::<_, u64, _>(&DummyStorage::new()
 			.with_header(test_header(0))
 			.with_header(test_header(1))
 			.with_header(test_header(2)),
-			&correct_id(0), &correct_id(2)).unwrap(), true);
+			(&correct_id(0)).into(), &correct_id(2)).unwrap(), true);
 		// when with DESC iterations we end up with the same block
 		assert_eq!(chain::is_connected_to_block::<_, u64, _>(&DummyStorage::new()
 			.with_header(test_header(0))
 			.with_header(test_header(1))
 			.with_header(test_header(2)),
-			&correct_id(2), &correct_id(0)).unwrap(), true);
+			(&correct_id(2)).into(), &correct_id(0)).unwrap(), true);
 	}
 
 	#[test]
@@ -1454,7 +1653,7 @@ pub mod tests {
 				.with_entry(test_id(10), StorageEntry { prev_valid_from: None, value: 10 })
 				.with_entry(test_id(20), StorageEntry { prev_valid_from: Some(test_id(10)), value: 20 })
 				.with_entry(test_id(30), StorageEntry { prev_valid_from: Some(test_id(20)), value: 30 }),
-			strategy, test_id(9));
+			strategy, test_id(9)).unwrap();
 			let mut tx = DummyTransaction::new();
 
 			// when finalizing entry #10: no entries pruned
@@ -1515,28 +1714,64 @@ pub mod tests {
 				.with_header(fork_header(1, 2, 5))
 				.with_header(fork_header(2, 4, 5)),
 			PruningStrategy::ByDepth(1024), correct_id(1)
-		);
+		).unwrap();
 
 		// when 5 is reverted: entry 5 is truncated
-		let op = cache.on_block_revert(&mut DummyTransaction::new(), &correct_id(5)).unwrap();
+		let op = cache.do_on_block_revert(&mut DummyTransaction::new(), &correct_id(5)).unwrap();
 		assert_eq!(op, CommitOperation::BlockReverted(vec![
 			(0, Some(Fork { best_block: None, head: Entry { valid_from: correct_id(4), value: 4 } })),
 		].into_iter().collect()));
-		cache.on_transaction_commit(op);
+		cache.on_transaction_commit(vec![op].into());
 
 		// when 3 is reverted: entries 4+5' are truncated
-		let op = cache.on_block_revert(&mut DummyTransaction::new(), &correct_id(3)).unwrap();
+		let op = cache.do_on_block_revert(&mut DummyTransaction::new(), &correct_id(3)).unwrap();
 		assert_eq!(op, CommitOperation::BlockReverted(vec![
 			(0, None),
 			(2, None),
 		].into_iter().collect()));
-		cache.on_transaction_commit(op);
+		cache.on_transaction_commit(vec![op].into());
 
 		// when 2 is reverted: entries 4'+5' are truncated
-		let op = cache.on_block_revert(&mut DummyTransaction::new(), &correct_id(2)).unwrap();
+		let op = cache.do_on_block_revert(&mut DummyTransaction::new(), &correct_id(2)).unwrap();
 		assert_eq!(op, CommitOperation::BlockReverted(vec![
 			(0, None),
 		].into_iter().collect()));
-		cache.on_transaction_commit(op);
+		cache.on_transaction_commit(vec![op].into());
+	}
+
+	#[test]
+	fn append_commit_operation_works() {
+		let mut ops = CommitOperations::default();
+		ops.append(None);
+		assert_eq!(ops.operations, Vec::new());
+
+		ops.append(Some(CommitOperation::BlockFinalized(
+			test_id(10),
+			Some(Entry { valid_from: test_id(10), value: 10 }),
+			vec![5].into_iter().collect(),
+		)));
+		assert_eq!(
+			ops.operations,
+			vec![CommitOperation::BlockFinalized(
+				test_id(10),
+				Some(Entry { valid_from: test_id(10), value: 10 }),
+				vec![5].into_iter().collect(),
+			)],
+		);
+
+		ops.append(Some(CommitOperation::BlockFinalized(
+			test_id(20),
+			Some(Entry { valid_from: test_id(20), value: 20 }),
+			vec![5, 6].into_iter().collect(),
+		)));
+		
+		assert_eq!(
+			ops.operations,
+			vec![CommitOperation::BlockFinalized(
+				test_id(20),
+				Some(Entry { valid_from: test_id(20), value: 20 }),
+				vec![5, 6].into_iter().collect(),
+			)],
+		);
 	}
 }
diff --git a/client/db/src/cache/list_storage.rs b/client/db/src/cache/list_storage.rs
index 9cd3b1049a4f8..606090ee1401d 100644
--- a/client/db/src/cache/list_storage.rs
+++ b/client/db/src/cache/list_storage.rs
@@ -222,7 +222,9 @@ mod meta {
 				unfinalized.push(&entry.valid_from);
 			},
 			CommitOperation::BlockFinalized(_, ref finalizing_entry, ref forks) => {
-				finalized = finalizing_entry.as_ref().map(|entry| &entry.valid_from);
+				if let Some(finalizing_entry) = finalizing_entry.as_ref() {
+					finalized = Some(&finalizing_entry.valid_from);
+				}
 				for fork_index in forks.iter().rev() {
 					unfinalized.remove(*fork_index);
 				}
diff --git a/client/db/src/cache/mod.rs b/client/db/src/cache/mod.rs
index bef8d9a7919d3..8fd1adc094ae4 100644
--- a/client/db/src/cache/mod.rs
+++ b/client/db/src/cache/mod.rs
@@ -16,7 +16,7 @@
 
 //! DB-backed cache of blockchain data.
 
-use std::{sync::Arc, collections::HashMap};
+use std::{sync::Arc, collections::{HashMap, hash_map::Entry}};
 use parking_lot::RwLock;
 
 use kvdb::{KeyValueDB, DBTransaction};
@@ -51,8 +51,10 @@ pub enum EntryType {
 /// Block identifier that holds both hash and number.
 #[derive(Clone, Debug, Encode, Decode, PartialEq)]
 pub struct ComplexBlockId<Block: BlockT> {
-	hash: Block::Hash,
-	number: NumberFor<Block>,
+	/// Hash of the block.
+	pub(crate) hash: Block::Hash,
+	/// Number of the block.
+	pub(crate) number: NumberFor<Block>,
 }
 
 impl<Block: BlockT> ComplexBlockId<Block> {
@@ -79,7 +81,7 @@ pub struct DbCache<Block: BlockT> {
 	db: Arc<dyn KeyValueDB>,
 	key_lookup_column: u32,
 	header_column: u32,
-	authorities_column: u32,
+	cache_column: u32,
 	genesis_hash: Block::Hash,
 	best_finalized_block: ComplexBlockId<Block>,
 }
@@ -90,7 +92,7 @@ impl<Block: BlockT> DbCache<Block> {
 		db: Arc<dyn KeyValueDB>,
 		key_lookup_column: u32,
 		header_column: u32,
-		authorities_column: u32,
+		cache_column: u32,
 		genesis_hash: Block::Hash,
 		best_finalized_block: ComplexBlockId<Block>,
 	) -> Self {
@@ -99,7 +101,7 @@ impl<Block: BlockT> DbCache<Block> {
 			db,
 			key_lookup_column,
 			header_column,
-			authorities_column,
+			cache_column,
 			genesis_hash,
 			best_finalized_block,
 		}
@@ -115,30 +117,48 @@ impl<Block: BlockT> DbCache<Block> {
 		DbCacheTransaction {
 			cache: self,
 			tx,
-			cache_at_op: HashMap::new(),
+			cache_at_ops: HashMap::new(),
 			best_finalized_block: None,
 		}
 	}
 
+	/// Begin cache transaction with given ops.
+	pub fn transaction_with_ops<'a>(
+		&'a mut self,
+		tx: &'a mut DBTransaction,
+		ops: DbCacheTransactionOps<Block>,
+	) -> DbCacheTransaction<'a, Block> {
+		DbCacheTransaction {
+			cache: self,
+			tx,
+			cache_at_ops: ops.cache_at_ops,
+			best_finalized_block: ops.best_finalized_block,
+		}
+	}
+
 	/// Run post-commit cache operations.
-	pub fn commit(&mut self, ops: DbCacheTransactionOps<Block>) {
-		for (name, op) in ops.cache_at_op.into_iter() {
-			self.get_cache(name).on_transaction_commit(op);
+	pub fn commit(&mut self, ops: DbCacheTransactionOps<Block>) -> ClientResult<()> {
+		for (name, ops) in ops.cache_at_ops.into_iter() {
+			self.get_cache(name)?.on_transaction_commit(ops);
 		}
 		if let Some(best_finalized_block) = ops.best_finalized_block {
 			self.best_finalized_block = best_finalized_block;
 		}
+		Ok(())
 	}
 
 	/// Creates `ListCache` with the given name or returns a reference to the existing.
-	fn get_cache(&mut self, name: CacheKeyId) -> &mut ListCache<Block, Vec<u8>, self::list_storage::DbStorage> {
+	pub(crate) fn get_cache(
+		&mut self,
+		name: CacheKeyId,
+	) -> ClientResult<&mut ListCache<Block, Vec<u8>, self::list_storage::DbStorage>> {
 		get_cache_helper(
 			&mut self.cache_at,
 			name,
 			&self.db,
 			self.key_lookup_column,
 			self.header_column,
-			self.authorities_column,
+			self.cache_column,
 			&self.best_finalized_block
 		)
 	}
@@ -154,34 +174,49 @@ fn get_cache_helper<'a, Block: BlockT>(
 	header: u32,
 	cache: u32,
 	best_finalized_block: &ComplexBlockId<Block>,
-) -> &'a mut ListCache<Block, Vec<u8>, self::list_storage::DbStorage> {
-	cache_at.entry(name).or_insert_with(|| {
-		ListCache::new(
-			self::list_storage::DbStorage::new(name.to_vec(), db.clone(),
-				self::list_storage::DbColumns {
-					meta: COLUMN_META,
-					key_lookup,
-					header,
-					cache,
-				},
-			),
-			cache_pruning_strategy(name),
-			best_finalized_block.clone(),
-		)
-	})
+) -> ClientResult<&'a mut ListCache<Block, Vec<u8>, self::list_storage::DbStorage>> {
+	match cache_at.entry(name) {
+		Entry::Occupied(entry) => Ok(entry.into_mut()),
+		Entry::Vacant(entry) => {
+			let cache = ListCache::new(
+				self::list_storage::DbStorage::new(name.to_vec(), db.clone(),
+					self::list_storage::DbColumns {
+						meta: COLUMN_META,
+						key_lookup,
+						header,
+						cache,
+					},
+				),
+				cache_pruning_strategy(name),
+				best_finalized_block.clone(),
+			)?;
+			Ok(entry.insert(cache))
+		}
+	}
 }
 
 /// Cache operations that are to be committed after database transaction is committed.
+#[derive(Default)]
 pub struct DbCacheTransactionOps<Block: BlockT> {
-	cache_at_op: HashMap<CacheKeyId, self::list_cache::CommitOperation<Block, Vec<u8>>>,
+	cache_at_ops: HashMap<CacheKeyId, self::list_cache::CommitOperations<Block, Vec<u8>>>,
 	best_finalized_block: Option<ComplexBlockId<Block>>,
 }
 
+impl<Block: BlockT> DbCacheTransactionOps<Block> {
+	/// Empty transaction ops.
+	pub fn empty() -> DbCacheTransactionOps<Block> {
+		DbCacheTransactionOps {
+			cache_at_ops: HashMap::new(),
+			best_finalized_block: None,
+		}
+	}
+}
+
 /// Database-backed blockchain data cache transaction valid for single block import.
 pub struct DbCacheTransaction<'a, Block: BlockT> {
 	cache: &'a mut DbCache<Block>,
 	tx: &'a mut DBTransaction,
-	cache_at_op: HashMap<CacheKeyId, self::list_cache::CommitOperation<Block, Vec<u8>>>,
+	cache_at_ops: HashMap<CacheKeyId, self::list_cache::CommitOperations<Block, Vec<u8>>>,
 	best_finalized_block: Option<ComplexBlockId<Block>>,
 }
 
@@ -189,7 +224,7 @@ impl<'a, Block: BlockT> DbCacheTransaction<'a, Block> {
 	/// Convert transaction into post-commit operations set.
 	pub fn into_ops(self) -> DbCacheTransactionOps<Block> {
 		DbCacheTransactionOps {
-			cache_at_op: self.cache_at_op,
+			cache_at_ops: self.cache_at_ops,
 			best_finalized_block: self.best_finalized_block,
 		}
 	}
@@ -202,8 +237,6 @@ impl<'a, Block: BlockT> DbCacheTransaction<'a, Block> {
 		data_at: HashMap<CacheKeyId, Vec<u8>>,
 		entry_type: EntryType,
 	) -> ClientResult<Self> {
-		assert!(self.cache_at_op.is_empty());
-
 		// prepare list of caches that are not update
 		// (we might still need to do some cache maintenance in this case)
 		let missed_caches = self.cache.cache_at.keys()
@@ -212,8 +245,9 @@ impl<'a, Block: BlockT> DbCacheTransaction<'a, Block> {
 			.collect::<Vec<_>>();
 
 		let mut insert_op = |name: CacheKeyId, value: Option<Vec<u8>>| -> Result<(), sp_blockchain::Error> {
-			let cache = self.cache.get_cache(name);
-			let op = cache.on_block_insert(
+			let cache = self.cache.get_cache(name)?;
+			let cache_ops = self.cache_at_ops.entry(name).or_default();
+			cache.on_block_insert(
 				&mut self::list_storage::DbStorageTransaction::new(
 					cache.storage(),
 					&mut self.tx,
@@ -222,10 +256,9 @@ impl<'a, Block: BlockT> DbCacheTransaction<'a, Block> {
 				block.clone(),
 				value,
 				entry_type,
+				cache_ops,
 			)?;
-			if let Some(op) = op {
-				self.cache_at_op.insert(name, op);
-			}
+
 			Ok(())
 		};
 
@@ -245,23 +278,19 @@ impl<'a, Block: BlockT> DbCacheTransaction<'a, Block> {
 	pub fn on_block_finalize(
 		mut self,
 		parent: ComplexBlockId<Block>,
-		block: ComplexBlockId<Block>
+		block: ComplexBlockId<Block>,
 	) -> ClientResult<Self> {
-		assert!(self.cache_at_op.is_empty());
-
-		for (name, cache_at) in self.cache.cache_at.iter() {
-			let op = cache_at.on_block_finalize(
+		for (name, cache) in self.cache.cache_at.iter() {
+			let cache_ops = self.cache_at_ops.entry(*name).or_default();
+			cache.on_block_finalize(
 				&mut self::list_storage::DbStorageTransaction::new(
-					cache_at.storage(),
+					cache.storage(),
 					&mut self.tx
 				),
 				parent.clone(),
 				block.clone(),
+				cache_ops,
 			)?;
-
-			if let Some(op) = op {
-				self.cache_at_op.insert(name.to_owned(), op);
-			}
 		}
 
 		self.best_finalized_block = Some(block);
@@ -275,16 +304,15 @@ impl<'a, Block: BlockT> DbCacheTransaction<'a, Block> {
 		reverted_block: &ComplexBlockId<Block>,
 	) -> ClientResult<Self> {
 		for (name, cache) in self.cache.cache_at.iter() {
-			let op = cache.on_block_revert(
+			let cache_ops = self.cache_at_ops.entry(*name).or_default();
+			cache.on_block_revert(
 				&mut self::list_storage::DbStorageTransaction::new(
 					cache.storage(),
 					&mut self.tx
 				),
 				reverted_block,
+				cache_ops,
 			)?;
-
-			assert!(!self.cache_at_op.contains_key(name));
-			self.cache_at_op.insert(name.to_owned(), op);
 		}
 
 		Ok(self)
@@ -310,7 +338,7 @@ impl<Block: BlockT> BlockchainCache<Block> for DbCacheSync<Block> {
 		)?;
 		let tx_ops = tx.into_ops();
 		db.write(dbtx).map_err(db_err)?;
-		cache.commit(tx_ops);
+		cache.commit(tx_ops)?;
 		Ok(())
 	}
 
@@ -318,40 +346,38 @@ impl<Block: BlockT> BlockchainCache<Block> for DbCacheSync<Block> {
 		&self,
 		key: &CacheKeyId,
 		at: &BlockId<Block>,
-	) -> Option<((NumberFor<Block>, Block::Hash), Option<(NumberFor<Block>, Block::Hash)>, Vec<u8>)> {
+	) -> ClientResult<Option<((NumberFor<Block>, Block::Hash), Option<(NumberFor<Block>, Block::Hash)>, Vec<u8>)>> {
 		let mut cache = self.0.write();
-		let storage = cache.get_cache(*key).storage();
+		let cache = cache.get_cache(*key)?;
+		let storage = cache.storage();
 		let db = storage.db();
 		let columns = storage.columns();
 		let at = match *at {
 			BlockId::Hash(hash) => {
-				let header = utils::read_header::<Block>(
+				let header = utils::require_header::<Block>(
 					&**db,
 					columns.key_lookup,
 					columns.header,
-					BlockId::Hash(hash.clone())).ok()??;
+					BlockId::Hash(hash.clone()))?;
 				ComplexBlockId::new(hash, *header.number())
 			},
 			BlockId::Number(number) => {
-				let hash = utils::read_header::<Block>(
+				let hash = utils::require_header::<Block>(
 					&**db,
 					columns.key_lookup,
 					columns.header,
-					BlockId::Number(number.clone())).ok()??.hash();
+					BlockId::Number(number.clone()))?.hash();
 				ComplexBlockId::new(hash, number)
 			},
 		};
 
-		cache.cache_at
-			.get(key)?
-			.value_at_block(&at)
+		cache.value_at_block(&at)
 			.map(|block_and_value| block_and_value.map(|(begin_block, end_block, value)|
 				(
 					(begin_block.number, begin_block.hash),
 					end_block.map(|end_block| (end_block.number, end_block.hash)),
 					value,
 				)))
-			.ok()?
 	}
 }
 
diff --git a/client/db/src/changes_tries_storage.rs b/client/db/src/changes_tries_storage.rs
new file mode 100644
index 0000000000000..72163a5694213
--- /dev/null
+++ b/client/db/src/changes_tries_storage.rs
@@ -0,0 +1,1015 @@
+// Copyright 2019 Parity Technologies (UK) Ltd.
+// This file is part of Substrate.
+
+// Substrate is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Substrate is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Substrate.  If not, see <http://www.gnu.org/licenses/>.
+
+//! DB-backed changes tries storage.
+
+use std::collections::{HashMap, HashSet};
+use std::sync::Arc;
+use hash_db::Prefix;
+use kvdb::{KeyValueDB, DBTransaction};
+use codec::{Decode, Encode};
+use parking_lot::RwLock;
+use sp_blockchain::{Error as ClientError, Result as ClientResult};
+use sp_trie::MemoryDB;
+use sc_client_api::backend::PrunableStateChangesTrieStorage;
+use sp_blockchain::{well_known_cache_keys, Cache as BlockchainCache};
+use sp_core::{ChangesTrieConfiguration, ChangesTrieConfigurationRange, convert_hash};
+use sp_runtime::traits::{
+	Block as BlockT, Header as HeaderT, HasherFor, NumberFor, One, Zero, CheckedSub,
+};
+use sp_runtime::generic::{BlockId, DigestItem, ChangesTrieSignal};
+use sp_state_machine::{DBValue, ChangesTrieBuildCache, ChangesTrieCacheAction};
+use crate::utils::{self, Meta, meta_keys, db_err};
+use crate::cache::{
+	DbCacheSync, DbCache, DbCacheTransactionOps,
+	ComplexBlockId, EntryType as CacheEntryType,
+};
+
+/// Extract new changes trie configuration (if available) from the header.
+pub fn extract_new_configuration<Header: HeaderT>(header: &Header) -> Option<&Option<ChangesTrieConfiguration>> {
+	header.digest()
+		.log(DigestItem::as_changes_trie_signal)
+		.and_then(ChangesTrieSignal::as_new_configuration)
+}
+
+/// Opaque configuration cache transaction. During its lifetime, no-one should modify cache. This is currently
+/// guaranteed because import lock is held during block import/finalization.
+pub struct DbChangesTrieStorageTransaction<Block: BlockT> {
+	/// Cache operations that must be performed after db transaction is comitted.
+	cache_ops: DbCacheTransactionOps<Block>,
+	/// New configuration (if changed at current block).
+	new_config: Option<Option<ChangesTrieConfiguration>>,
+}
+
+impl<Block: BlockT> DbChangesTrieStorageTransaction<Block> {
+	/// Consume self and return transaction with given new configuration.
+	pub fn with_new_config(mut self, new_config: Option<Option<ChangesTrieConfiguration>>) -> Self {
+		self.new_config = new_config;
+		self
+	}
+}
+
+impl<Block: BlockT> From<DbCacheTransactionOps<Block>> for DbChangesTrieStorageTransaction<Block> {
+	fn from(cache_ops: DbCacheTransactionOps<Block>) -> Self {
+		DbChangesTrieStorageTransaction {
+			cache_ops,
+			new_config: None,
+		}
+	}
+}
+
+/// Changes tries storage.
+///
+/// Stores all tries in separate DB column.
+/// Lock order: meta, tries_meta, cache, build_cache.
+pub struct DbChangesTrieStorage<Block: BlockT> {
+	db: Arc<dyn KeyValueDB>,
+	meta_column: u32,
+	changes_tries_column: u32,
+	key_lookup_column: u32,
+	header_column: u32,
+	meta: Arc<RwLock<Meta<NumberFor<Block>, Block::Hash>>>,
+	tries_meta: RwLock<ChangesTriesMeta<Block>>,
+	min_blocks_to_keep: Option<u32>,
+	/// The cache stores all ever existing changes tries configurations.
+	cache: DbCacheSync<Block>,
+	/// Build cache is a map of block => set of storage keys changed at this block.
+	/// They're used to build digest blocks - instead of reading+parsing tries from db
+	/// we just use keys sets from the cache.
+	build_cache: RwLock<ChangesTrieBuildCache<Block::Hash, NumberFor<Block>>>,
+}
+
+/// Persistent struct that contains all the changes tries metadata.
+#[derive(Decode, Encode, Debug)]
+struct ChangesTriesMeta<Block: BlockT> {
+	/// Oldest unpruned max-level (or skewed) digest trie blocks range.
+	/// The range is inclusive from both sides.
+	/// Is None only if:
+	/// 1) we haven't yet finalized any blocks (except genesis)
+	/// 2) if best_finalized_block - min_blocks_to_keep points to the range where changes tries are disabled
+	/// 3) changes tries pruning is disabled
+	pub oldest_digest_range: Option<(NumberFor<Block>, NumberFor<Block>)>,
+	/// End block (inclusive) of oldest pruned max-level (or skewed) digest trie blocks range.
+	/// It is guaranteed that we have no any changes tries before (and including) this block.
+	/// It is guaranteed that all existing changes tries after this block are not yet pruned (if created).
+	pub oldest_pruned_digest_range_end: NumberFor<Block>,
+}
+
+impl<Block: BlockT> DbChangesTrieStorage<Block> {
+	/// Create new changes trie storage.
+	pub fn new(
+		db: Arc<dyn KeyValueDB>,
+		meta_column: u32,
+		changes_tries_column: u32,
+		key_lookup_column: u32,
+		header_column: u32,
+		cache_column: u32,
+		meta: Arc<RwLock<Meta<NumberFor<Block>, Block::Hash>>>,
+		min_blocks_to_keep: Option<u32>,
+	) -> ClientResult<Self> {
+		let (finalized_hash, finalized_number, genesis_hash) = {
+			let meta = meta.read();
+			(meta.finalized_hash, meta.finalized_number, meta.genesis_hash)
+		};
+		let tries_meta = read_tries_meta(&*db, meta_column)?;
+		Ok(Self {
+			db: db.clone(),
+			meta_column,
+			changes_tries_column,
+			key_lookup_column,
+			header_column,
+			meta,
+			min_blocks_to_keep,
+			cache: DbCacheSync(RwLock::new(DbCache::new(
+				db.clone(),
+				key_lookup_column,
+				header_column,
+				cache_column,
+				genesis_hash,
+				ComplexBlockId::new(finalized_hash, finalized_number),
+			))),
+			build_cache: RwLock::new(ChangesTrieBuildCache::new()),
+			tries_meta: RwLock::new(tries_meta),
+		})
+	}
+
+	/// Commit new changes trie.
+	pub fn commit(
+		&self,
+		tx: &mut DBTransaction,
+		mut changes_trie: MemoryDB<HasherFor<Block>>,
+		parent_block: ComplexBlockId<Block>,
+		block: ComplexBlockId<Block>,
+		new_header: &Block::Header,
+		finalized: bool,
+		new_configuration: Option<Option<ChangesTrieConfiguration>>,
+		cache_tx: Option<DbChangesTrieStorageTransaction<Block>>,
+	) -> ClientResult<DbChangesTrieStorageTransaction<Block>> {
+		// insert changes trie, associated with block, into DB
+		for (key, (val, _)) in changes_trie.drain() {
+			tx.put(self.changes_tries_column, key.as_ref(), &val);
+		}
+
+		// if configuration has not been changed AND block is not finalized => nothing to do here
+		let new_configuration = match new_configuration {
+			Some(new_configuration) => new_configuration,
+			None if !finalized => return Ok(DbCacheTransactionOps::empty().into()),
+			None => return self.finalize(
+				tx,
+				parent_block.hash,
+				block.hash,
+				block.number,
+				Some(new_header),
+				cache_tx,
+			),
+		};
+
+		// update configuration cache
+		let mut cache_at = HashMap::new();
+		cache_at.insert(well_known_cache_keys::CHANGES_TRIE_CONFIG, new_configuration.encode());
+		Ok(DbChangesTrieStorageTransaction::from(match cache_tx {
+			Some(cache_tx) => self.cache.0.write()
+				.transaction_with_ops(tx, cache_tx.cache_ops)
+				.on_block_insert(
+					parent_block,
+					block,
+					cache_at,
+					if finalized { CacheEntryType::Final } else { CacheEntryType::NonFinal },
+				)?
+				.into_ops(),
+			None => self.cache.0.write()
+				.transaction(tx)
+				.on_block_insert(
+					parent_block,
+					block,
+					cache_at,
+					if finalized { CacheEntryType::Final } else { CacheEntryType::NonFinal },
+				)?
+				.into_ops(),
+		}).with_new_config(Some(new_configuration)))
+	}
+
+	/// Called when block is finalized.
+	pub fn finalize(
+		&self,
+		tx: &mut DBTransaction,
+		parent_block_hash: Block::Hash,
+		block_hash: Block::Hash,
+		block_num: NumberFor<Block>,
+		new_header: Option<&Block::Header>,
+		cache_tx: Option<DbChangesTrieStorageTransaction<Block>>,
+	) -> ClientResult<DbChangesTrieStorageTransaction<Block>> {
+		// prune obsolete changes tries
+		self.prune(tx, block_hash, block_num, new_header.clone(), cache_tx.as_ref())?;
+
+		// if we have inserted the block that we're finalizing in the same transaction
+		// => then we have already finalized it from the commit() call
+		if cache_tx.is_some() {
+			if let Some(new_header) = new_header {
+				if new_header.hash() == block_hash {
+					return Ok(cache_tx.expect("guarded by cache_tx.is_some(); qed"));
+				}
+			}
+		}
+
+		// and finalize configuration cache entries
+		let block = ComplexBlockId::new(block_hash, block_num);
+		let parent_block_num = block_num.checked_sub(&One::one()).unwrap_or_else(|| Zero::zero());
+		let parent_block = ComplexBlockId::new(parent_block_hash, parent_block_num);
+		Ok(match cache_tx {
+			Some(cache_tx) => DbChangesTrieStorageTransaction::from(
+				self.cache.0.write()
+					.transaction_with_ops(tx, cache_tx.cache_ops)
+					.on_block_finalize(
+						parent_block,
+						block,
+					)?
+					.into_ops()
+			).with_new_config(cache_tx.new_config),
+			None => DbChangesTrieStorageTransaction::from(
+				self.cache.0.write()
+					.transaction(tx)
+					.on_block_finalize(
+						parent_block,
+						block,
+					)?
+					.into_ops()
+			),
+		})
+	}
+
+	/// When block is reverted.
+	pub fn revert(
+		&self,
+		tx: &mut DBTransaction,
+		block: &ComplexBlockId<Block>,
+	) -> ClientResult<DbChangesTrieStorageTransaction<Block>> {
+		Ok(self.cache.0.write().transaction(tx)
+			.on_block_revert(block)?
+			.into_ops()
+			.into())
+	}
+
+	/// When transaction has been committed.
+	pub fn post_commit(&self, tx: Option<DbChangesTrieStorageTransaction<Block>>) {
+		if let Some(tx) = tx {
+			self.cache.0.write().commit(tx.cache_ops)
+				.expect("only fails if cache with given name isn't loaded yet;\
+						cache is already loaded because there is tx; qed");
+		}
+	}
+
+	/// Commit changes into changes trie build cache.
+	pub fn commit_build_cache(&self, cache_update: ChangesTrieCacheAction<Block::Hash, NumberFor<Block>>) {
+		self.build_cache.write().perform(cache_update);
+	}
+
+	/// Prune obsolete changes tries.
+	fn prune(
+		&self,
+		tx: &mut DBTransaction,
+		block_hash: Block::Hash,
+		block_num: NumberFor<Block>,
+		new_header: Option<&Block::Header>,
+		cache_tx: Option<&DbChangesTrieStorageTransaction<Block>>,
+	) -> ClientResult<()> {
+		// never prune on archive nodes
+		let min_blocks_to_keep = match self.min_blocks_to_keep {
+			Some(min_blocks_to_keep) => min_blocks_to_keep,
+			None => return Ok(()),
+		};
+
+		let mut tries_meta = self.tries_meta.write();
+		let mut next_digest_range_start = block_num;
+		loop {
+			// prune oldest digest if it is known
+			// it could be unknown if:
+			// 1) either we're finalizing block#1
+			// 2) or we are (or were) in period where changes tries are disabled
+			if let Some((begin, end)) = tries_meta.oldest_digest_range {
+				if block_num <= end || block_num - end <= min_blocks_to_keep.into() {
+					break;
+				}
+
+				tries_meta.oldest_pruned_digest_range_end = end;
+				sp_state_machine::prune_changes_tries(
+					&*self,
+					begin,
+					end,
+					&sp_state_machine::ChangesTrieAnchorBlockId {
+						hash: convert_hash(&block_hash),
+						number: block_num,
+					},
+					|node| tx.delete(self.changes_tries_column, node.as_ref()),
+				);
+
+				next_digest_range_start = end + One::one();
+			}
+
+			// proceed to the next configuration range
+			let next_digest_range_start_hash = match block_num == next_digest_range_start {
+				true => block_hash,
+				false => utils::require_header::<Block>(
+					&*self.db,
+					self.key_lookup_column,
+					self.header_column,
+					BlockId::Number(next_digest_range_start),
+				)?.hash(),
+			};
+
+			let config_for_new_block = new_header
+				.map(|header| *header.number() == next_digest_range_start)
+				.unwrap_or(false);
+			let next_config = match cache_tx {
+				Some(cache_tx) if config_for_new_block && cache_tx.new_config.is_some() => {
+					let config = cache_tx
+						.new_config
+						.clone()
+						.expect("guarded by is_some(); qed");
+					ChangesTrieConfigurationRange {
+						zero: (block_num, block_hash),
+						end: None,
+						config,
+					}
+				},
+				_ if config_for_new_block => {
+					self.configuration_at(&BlockId::Hash(*new_header.expect(
+						"config_for_new_block is only true when new_header is passed; qed"
+					).parent_hash()))?
+				},
+				_ => self.configuration_at(&BlockId::Hash(next_digest_range_start_hash))?,
+			};
+			if let Some(config) = next_config.config {
+				let mut oldest_digest_range = config
+					.next_max_level_digest_range(next_config.zero.0, next_digest_range_start)
+					.unwrap_or_else(|| (next_digest_range_start, next_digest_range_start));
+
+				if let Some(end) = next_config.end {
+					if end.0 < oldest_digest_range.1 {
+						oldest_digest_range.1 = end.0;
+					}
+				}
+
+				tries_meta.oldest_digest_range = Some(oldest_digest_range);
+				continue;
+			}
+
+			tries_meta.oldest_digest_range = None;
+			break;
+		}
+
+		write_tries_meta(tx, self.meta_column, &*tries_meta);
+		Ok(())
+	}
+}
+
+impl<Block: BlockT> PrunableStateChangesTrieStorage<Block> for DbChangesTrieStorage<Block> {
+	fn storage(&self) -> &dyn sp_state_machine::ChangesTrieStorage<HasherFor<Block>, NumberFor<Block>> {
+		self
+	}
+
+	fn configuration_at(&self, at: &BlockId<Block>) -> ClientResult<
+		ChangesTrieConfigurationRange<NumberFor<Block>, Block::Hash>
+	> {
+		self.cache
+			.get_at(&well_known_cache_keys::CHANGES_TRIE_CONFIG, at)?
+			.and_then(|(zero, end, encoded)| Decode::decode(&mut &encoded[..]).ok()
+				.map(|config| ChangesTrieConfigurationRange { zero, end, config }))
+			.ok_or_else(|| ClientError::ErrorReadingChangesTriesConfig)
+	}
+
+	fn oldest_pruned_digest_range_end(&self) -> NumberFor<Block> {
+		self.tries_meta.read().oldest_pruned_digest_range_end
+	}
+}
+
+impl<Block: BlockT> sp_state_machine::ChangesTrieRootsStorage<HasherFor<Block>, NumberFor<Block>>
+	for DbChangesTrieStorage<Block>
+{
+	fn build_anchor(
+		&self,
+		hash: Block::Hash,
+	) -> Result<sp_state_machine::ChangesTrieAnchorBlockId<Block::Hash, NumberFor<Block>>, String> {
+		utils::read_header::<Block>(&*self.db, self.key_lookup_column, self.header_column, BlockId::Hash(hash))
+			.map_err(|e| e.to_string())
+			.and_then(|maybe_header| maybe_header.map(|header|
+				sp_state_machine::ChangesTrieAnchorBlockId {
+					hash,
+					number: *header.number(),
+				}
+			).ok_or_else(|| format!("Unknown header: {}", hash)))
+	}
+
+	fn root(
+		&self,
+		anchor: &sp_state_machine::ChangesTrieAnchorBlockId<Block::Hash, NumberFor<Block>>,
+		block: NumberFor<Block>,
+	) -> Result<Option<Block::Hash>, String> {
+		// check API requirement: we can't get NEXT block(s) based on anchor
+		if block > anchor.number {
+			return Err(format!("Can't get changes trie root at {} using anchor at {}", block, anchor.number));
+		}
+
+		// we need to get hash of the block to resolve changes trie root
+		let block_id = if block <= self.meta.read().finalized_number {
+			// if block is finalized, we could just read canonical hash
+			BlockId::Number(block)
+		} else {
+			// the block is not finalized
+			let mut current_num = anchor.number;
+			let mut current_hash: Block::Hash = convert_hash(&anchor.hash);
+			let maybe_anchor_header: Block::Header = utils::require_header::<Block>(
+				&*self.db, self.key_lookup_column, self.header_column, BlockId::Number(current_num)
+			).map_err(|e| e.to_string())?;
+			if maybe_anchor_header.hash() == current_hash {
+				// if anchor is canonicalized, then the block is also canonicalized
+				BlockId::Number(block)
+			} else {
+				// else (block is not finalized + anchor is not canonicalized):
+				// => we should find the required block hash by traversing
+				// back from the anchor to the block with given number
+				while current_num != block {
+					let current_header: Block::Header = utils::require_header::<Block>(
+						&*self.db, self.key_lookup_column, self.header_column, BlockId::Hash(current_hash)
+					).map_err(|e| e.to_string())?;
+
+					current_hash = *current_header.parent_hash();
+					current_num = current_num - One::one();
+				}
+
+				BlockId::Hash(current_hash)
+			}
+		};
+
+		Ok(
+			utils::require_header::<Block>(
+				&*self.db,
+				self.key_lookup_column,
+				self.header_column,
+				block_id,
+			)
+			.map_err(|e| e.to_string())?
+			.digest()
+			.log(DigestItem::as_changes_trie_root)
+			.cloned()
+		)
+	}
+}
+
+impl<Block> sp_state_machine::ChangesTrieStorage<HasherFor<Block>, NumberFor<Block>>
+	for DbChangesTrieStorage<Block>
+where
+	Block: BlockT,
+{
+	fn as_roots_storage(&self) -> &dyn sp_state_machine::ChangesTrieRootsStorage<HasherFor<Block>, NumberFor<Block>> {
+		self
+	}
+
+	fn with_cached_changed_keys(
+		&self,
+		root: &Block::Hash,
+		functor: &mut dyn FnMut(&HashMap<Option<Vec<u8>>, HashSet<Vec<u8>>>),
+	) -> bool {
+		self.build_cache.read().with_changed_keys(root, functor)
+	}
+
+	fn get(&self, key: &Block::Hash, _prefix: Prefix) -> Result<Option<DBValue>, String> {
+		self.db.get(self.changes_tries_column, key.as_ref())
+			.map_err(|err| format!("{}", err))
+	}
+}
+
+/// Read changes tries metadata from database.
+fn read_tries_meta<Block: BlockT>(
+	db: &dyn KeyValueDB,
+	meta_column: u32,
+) -> ClientResult<ChangesTriesMeta<Block>> {
+	match db.get(meta_column, meta_keys::CHANGES_TRIES_META).map_err(db_err)? {
+		Some(h) => match Decode::decode(&mut &h[..]) {
+			Ok(h) => Ok(h),
+			Err(err) => Err(ClientError::Backend(format!("Error decoding changes tries metadata: {}", err))),
+		},
+		None => Ok(ChangesTriesMeta {
+			oldest_digest_range: None,
+			oldest_pruned_digest_range_end: Zero::zero(),
+		}),
+	}
+}
+
+/// Write changes tries metadata from database.
+fn write_tries_meta<Block: BlockT>(
+	tx: &mut DBTransaction,
+	meta_column: u32,
+	meta: &ChangesTriesMeta<Block>,
+) {
+	tx.put(meta_column, meta_keys::CHANGES_TRIES_META, &meta.encode());
+}
+
+#[cfg(test)]
+mod tests {
+	use hash_db::EMPTY_PREFIX;
+	use sc_client_api::backend::{
+		Backend as ClientBackend, NewBlockState, BlockImportOperation, PrunableStateChangesTrieStorage,
+	};
+	use sp_blockchain::HeaderBackend as BlockchainHeaderBackend;
+	use sp_core::H256;
+	use sp_runtime::testing::{Digest, Header};
+	use sp_runtime::traits::{Hash, BlakeTwo256};
+	use sp_state_machine::{ChangesTrieRootsStorage, ChangesTrieStorage};
+	use crate::Backend;
+	use crate::tests::{Block, insert_header, prepare_changes};
+	use super::*;
+
+	fn changes(number: u64) -> Option<Vec<(Vec<u8>, Vec<u8>)>> {
+		Some(vec![(number.to_le_bytes().to_vec(), number.to_le_bytes().to_vec())])
+	}
+
+	fn insert_header_with_configuration_change(
+		backend: &Backend<Block>,
+		number: u64,
+		parent_hash: H256,
+		changes: Option<Vec<(Vec<u8>, Vec<u8>)>>,
+		new_configuration: Option<ChangesTrieConfiguration>,
+	) -> H256 {
+		let mut digest = Digest::default();
+		let mut changes_trie_update = Default::default();
+		if let Some(changes) = changes {
+			let (root, update) = prepare_changes(changes);
+			digest.push(DigestItem::ChangesTrieRoot(root));
+			changes_trie_update = update;
+		}
+		digest.push(DigestItem::ChangesTrieSignal(ChangesTrieSignal::NewConfiguration(new_configuration)));
+
+		let header = Header {
+			number,
+			parent_hash,
+			state_root: BlakeTwo256::trie_root(Vec::new()),
+			digest,
+			extrinsics_root: Default::default(),
+		};
+		let header_hash = header.hash();
+
+		let block_id = if number == 0 {
+			BlockId::Hash(Default::default())
+		} else {
+			BlockId::Number(number - 1)
+		};
+		let mut op = backend.begin_operation().unwrap();
+		backend.begin_state_operation(&mut op, block_id).unwrap();
+		op.set_block_data(header, None, None, NewBlockState::Best).unwrap();
+		op.update_changes_trie((changes_trie_update, ChangesTrieCacheAction::Clear)).unwrap();
+		backend.commit_operation(op).unwrap();
+
+		header_hash
+	}
+
+	#[test]
+	fn changes_trie_storage_works() {
+		let backend = Backend::<Block>::new_test(1000, 100);
+		backend.changes_tries_storage.meta.write().finalized_number = 1000;
+
+		let check_changes = |backend: &Backend<Block>, block: u64, changes: Vec<(Vec<u8>, Vec<u8>)>| {
+			let (changes_root, mut changes_trie_update) = prepare_changes(changes);
+			let anchor = sp_state_machine::ChangesTrieAnchorBlockId {
+				hash: backend.blockchain().header(BlockId::Number(block)).unwrap().unwrap().hash(),
+				number: block
+			};
+			assert_eq!(backend.changes_tries_storage.root(&anchor, block), Ok(Some(changes_root)));
+
+			let storage = backend.changes_tries_storage.storage();
+			for (key, (val, _)) in changes_trie_update.drain() {
+				assert_eq!(storage.get(&key, EMPTY_PREFIX), Ok(Some(val)));
+			}
+		};
+
+		let changes0 = vec![(b"key_at_0".to_vec(), b"val_at_0".to_vec())];
+		let changes1 = vec![
+			(b"key_at_1".to_vec(), b"val_at_1".to_vec()),
+			(b"another_key_at_1".to_vec(), b"another_val_at_1".to_vec()),
+		];
+		let changes2 = vec![(b"key_at_2".to_vec(), b"val_at_2".to_vec())];
+
+		let block0 = insert_header(&backend, 0, Default::default(), Some(changes0.clone()), Default::default());
+		let block1 = insert_header(&backend, 1, block0, Some(changes1.clone()), Default::default());
+		let _ = insert_header(&backend, 2, block1, Some(changes2.clone()), Default::default());
+
+		// check that the storage contains tries for all blocks
+		check_changes(&backend, 0, changes0);
+		check_changes(&backend, 1, changes1);
+		check_changes(&backend, 2, changes2);
+	}
+
+	#[test]
+	fn changes_trie_storage_works_with_forks() {
+		let backend = Backend::<Block>::new_test(1000, 100);
+
+		let changes0 = vec![(b"k0".to_vec(), b"v0".to_vec())];
+		let changes1 = vec![(b"k1".to_vec(), b"v1".to_vec())];
+		let changes2 = vec![(b"k2".to_vec(), b"v2".to_vec())];
+		let block0 = insert_header(&backend, 0, Default::default(), Some(changes0.clone()), Default::default());
+		let block1 = insert_header(&backend, 1, block0, Some(changes1.clone()), Default::default());
+		let block2 = insert_header(&backend, 2, block1, Some(changes2.clone()), Default::default());
+
+		let changes2_1_0 = vec![(b"k3".to_vec(), b"v3".to_vec())];
+		let changes2_1_1 = vec![(b"k4".to_vec(), b"v4".to_vec())];
+		let block2_1_0 = insert_header(&backend, 3, block2, Some(changes2_1_0.clone()), Default::default());
+		let block2_1_1 = insert_header(&backend, 4, block2_1_0, Some(changes2_1_1.clone()), Default::default());
+
+		let changes2_2_0 = vec![(b"k5".to_vec(), b"v5".to_vec())];
+		let changes2_2_1 = vec![(b"k6".to_vec(), b"v6".to_vec())];
+		let block2_2_0 = insert_header(&backend, 3, block2, Some(changes2_2_0.clone()), Default::default());
+		let block2_2_1 = insert_header(&backend, 4, block2_2_0, Some(changes2_2_1.clone()), Default::default());
+
+		// finalize block1
+		backend.changes_tries_storage.meta.write().finalized_number = 1;
+
+		// branch1: when asking for finalized block hash
+		let (changes1_root, _) = prepare_changes(changes1);
+		let anchor = sp_state_machine::ChangesTrieAnchorBlockId { hash: block2_1_1, number: 4 };
+		assert_eq!(backend.changes_tries_storage.root(&anchor, 1), Ok(Some(changes1_root)));
+
+		// branch2: when asking for finalized block hash
+		let anchor = sp_state_machine::ChangesTrieAnchorBlockId { hash: block2_2_1, number: 4 };
+		assert_eq!(backend.changes_tries_storage.root(&anchor, 1), Ok(Some(changes1_root)));
+
+		// branch1: when asking for non-finalized block hash (search by traversal)
+		let (changes2_1_0_root, _) = prepare_changes(changes2_1_0);
+		let anchor = sp_state_machine::ChangesTrieAnchorBlockId { hash: block2_1_1, number: 4 };
+		assert_eq!(backend.changes_tries_storage.root(&anchor, 3), Ok(Some(changes2_1_0_root)));
+
+		// branch2: when asking for non-finalized block hash (search using canonicalized hint)
+		let (changes2_2_0_root, _) = prepare_changes(changes2_2_0);
+		let anchor = sp_state_machine::ChangesTrieAnchorBlockId { hash: block2_2_1, number: 4 };
+		assert_eq!(backend.changes_tries_storage.root(&anchor, 3), Ok(Some(changes2_2_0_root)));
+
+		// finalize first block of branch2 (block2_2_0)
+		backend.changes_tries_storage.meta.write().finalized_number = 3;
+
+		// branch2: when asking for finalized block of this branch
+		assert_eq!(backend.changes_tries_storage.root(&anchor, 3), Ok(Some(changes2_2_0_root)));
+
+		// branch1: when asking for finalized block of other branch
+		// => result is incorrect (returned for the block of branch1), but this is expected,
+		// because the other fork is abandoned (forked before finalized header)
+		let anchor = sp_state_machine::ChangesTrieAnchorBlockId { hash: block2_1_1, number: 4 };
+		assert_eq!(backend.changes_tries_storage.root(&anchor, 3), Ok(Some(changes2_2_0_root)));
+	}
+
+	#[test]
+	fn changes_tries_are_pruned_on_finalization() {
+		let mut backend = Backend::<Block>::new_test(1000, 100);
+		backend.changes_tries_storage.min_blocks_to_keep = Some(8);
+
+		let parent_hash = |number| {
+			if number == 0 {
+				Default::default()
+			} else {
+				backend.blockchain().header(BlockId::Number(number - 1)).unwrap().unwrap().hash()
+			}
+		};
+
+		let insert_regular_header = |with_changes, number| {
+			insert_header(
+				&backend,
+				number,
+				parent_hash(number),
+				if with_changes { changes(number) } else { None },
+				Default::default(),
+			);
+		};
+
+		let is_pruned = |number| {
+			let trie_root = backend
+				.blockchain()
+				.header(BlockId::Number(number))
+				.unwrap().unwrap()
+				.digest()
+				.log(DigestItem::as_changes_trie_root)
+				.cloned();
+			match trie_root {
+				Some(trie_root) => backend.changes_tries_storage.get(&trie_root, EMPTY_PREFIX).unwrap().is_none(),
+				None => true,
+			}
+		};
+
+		let finalize_block = |number| {
+			let header = backend.blockchain().header(BlockId::Number(number)).unwrap().unwrap();
+			let mut tx = DBTransaction::new();
+			let cache_ops = backend.changes_tries_storage.finalize(
+				&mut tx,
+				*header.parent_hash(),
+				header.hash(),
+				number,
+				None,
+				None,
+			).unwrap();
+			backend.storage.db.write(tx).unwrap();
+			backend.changes_tries_storage.post_commit(Some(cache_ops));
+		};
+
+		// configuration ranges:
+		// (0; 6] - None
+		// [7; 17] - Some(2^2): D2 is built at #10, #14; SD is built at #17
+		// [18; 21] - None
+		// [22; 32] - Some(8^1): D1 is built at #29; SD is built at #32
+		// [33; ... - Some(1)
+		let config_at_6 = Some(ChangesTrieConfiguration::new(2, 2));
+		let config_at_17 = None;
+		let config_at_21 = Some(ChangesTrieConfiguration::new(8, 1));
+		let config_at_32 = Some(ChangesTrieConfiguration::new(1, 0));
+
+		(0..6).for_each(|number| insert_regular_header(false, number));
+		insert_header_with_configuration_change(&backend, 6, parent_hash(6), None, config_at_6);
+		(7..17).for_each(|number| insert_regular_header(true, number));
+		insert_header_with_configuration_change(&backend, 17, parent_hash(17), changes(17), config_at_17);
+		(18..21).for_each(|number| insert_regular_header(false, number));
+		insert_header_with_configuration_change(&backend, 21, parent_hash(21), None, config_at_21);
+		(22..32).for_each(|number| insert_regular_header(true, number));
+		insert_header_with_configuration_change(&backend, 32, parent_hash(32), changes(32), config_at_32);
+		(33..50).for_each(|number| insert_regular_header(true, number));
+
+		// when only genesis is finalized, nothing is pruned
+		(0..=6).for_each(|number| assert!(is_pruned(number)));
+		(7..=17).for_each(|number| assert!(!is_pruned(number)));
+		(18..=21).for_each(|number| assert!(is_pruned(number)));
+		(22..50).for_each(|number| assert!(!is_pruned(number)));
+
+		// when blocks [1; 18] are finalized, nothing is pruned
+		(1..=18).for_each(|number| finalize_block(number));
+		(0..=6).for_each(|number| assert!(is_pruned(number)));
+		(7..=17).for_each(|number| assert!(!is_pruned(number)));
+		(18..=21).for_each(|number| assert!(is_pruned(number)));
+		(22..50).for_each(|number| assert!(!is_pruned(number)));
+
+		// when block 19 is finalized, changes tries for blocks [7; 10] are pruned
+		finalize_block(19);
+		(0..=10).for_each(|number| assert!(is_pruned(number)));
+		(11..=17).for_each(|number| assert!(!is_pruned(number)));
+		(18..=21).for_each(|number| assert!(is_pruned(number)));
+		(22..50).for_each(|number| assert!(!is_pruned(number)));
+
+		// when blocks [20; 22] are finalized, nothing is pruned
+		(20..=22).for_each(|number| finalize_block(number));
+		(0..=10).for_each(|number| assert!(is_pruned(number)));
+		(11..=17).for_each(|number| assert!(!is_pruned(number)));
+		(18..=21).for_each(|number| assert!(is_pruned(number)));
+		(22..50).for_each(|number| assert!(!is_pruned(number)));
+
+		// when block 23 is finalized, changes tries for blocks [11; 14] are pruned
+		finalize_block(23);
+		(0..=14).for_each(|number| assert!(is_pruned(number)));
+		(15..=17).for_each(|number| assert!(!is_pruned(number)));
+		(18..=21).for_each(|number| assert!(is_pruned(number)));
+		(22..50).for_each(|number| assert!(!is_pruned(number)));
+
+		// when blocks [24; 25] are finalized, nothing is pruned
+		(24..=25).for_each(|number| finalize_block(number));
+		(0..=14).for_each(|number| assert!(is_pruned(number)));
+		(15..=17).for_each(|number| assert!(!is_pruned(number)));
+		(18..=21).for_each(|number| assert!(is_pruned(number)));
+		(22..50).for_each(|number| assert!(!is_pruned(number)));
+
+		// when block 26 is finalized, changes tries for blocks [15; 17] are pruned
+		finalize_block(26);
+		(0..=21).for_each(|number| assert!(is_pruned(number)));
+		(22..50).for_each(|number| assert!(!is_pruned(number)));
+
+		// when blocks [27; 37] are finalized, nothing is pruned
+		(27..=37).for_each(|number| finalize_block(number));
+		(0..=21).for_each(|number| assert!(is_pruned(number)));
+		(22..50).for_each(|number| assert!(!is_pruned(number)));
+
+		// when block 38 is finalized, changes tries for blocks [22; 29] are pruned
+		finalize_block(38);
+		(0..=29).for_each(|number| assert!(is_pruned(number)));
+		(30..50).for_each(|number| assert!(!is_pruned(number)));
+
+		// when blocks [39; 40] are finalized, nothing is pruned
+		(39..=40).for_each(|number| finalize_block(number));
+		(0..=29).for_each(|number| assert!(is_pruned(number)));
+		(30..50).for_each(|number| assert!(!is_pruned(number)));
+
+		// when block 41 is finalized, changes tries for blocks [30; 32] are pruned
+		finalize_block(41);
+		(0..=32).for_each(|number| assert!(is_pruned(number)));
+		(33..50).for_each(|number| assert!(!is_pruned(number)));
+
+		// when block 42 is finalized, changes trie for block 33 is pruned
+		finalize_block(42);
+		(0..=33).for_each(|number| assert!(is_pruned(number)));
+		(34..50).for_each(|number| assert!(!is_pruned(number)));
+
+		// when block 43 is finalized, changes trie for block 34 is pruned
+		finalize_block(43);
+		(0..=34).for_each(|number| assert!(is_pruned(number)));
+		(35..50).for_each(|number| assert!(!is_pruned(number)));
+	}
+
+	#[test]
+	fn changes_tries_configuration_is_updated_on_block_insert() {
+		let backend = Backend::<Block>::new_test(1000, 100);
+
+		// configurations at blocks
+		let config_at_1 = Some(ChangesTrieConfiguration {
+			digest_interval: 4,
+			digest_levels: 2,
+		});
+		let config_at_3 = Some(ChangesTrieConfiguration {
+			digest_interval: 8,
+			digest_levels: 1,
+		});
+		let config_at_5 = None;
+		let config_at_7 = Some(ChangesTrieConfiguration {
+			digest_interval: 8,
+			digest_levels: 1,
+		});
+
+		// insert some blocks
+		let block0 = insert_header(&backend, 0, Default::default(), None, Default::default());
+		let block1 = insert_header_with_configuration_change(&backend, 1, block0, None, config_at_1.clone());
+		let block2 = insert_header(&backend, 2, block1, None, Default::default());
+		let block3 = insert_header_with_configuration_change(&backend, 3, block2, None, config_at_3.clone());
+		let block4 = insert_header(&backend, 4, block3, None, Default::default());
+		let block5 = insert_header_with_configuration_change(&backend, 5, block4, None, config_at_5.clone());
+		let block6 = insert_header(&backend, 6, block5, None, Default::default());
+		let block7 = insert_header_with_configuration_change(&backend, 7, block6, None, config_at_7.clone());
+
+		// test configuration cache
+		let storage = &backend.changes_tries_storage;
+		assert_eq!(
+			storage.configuration_at(&BlockId::Hash(block1)).unwrap().config,
+			config_at_1.clone(),
+		);
+		assert_eq!(
+			storage.configuration_at(&BlockId::Hash(block2)).unwrap().config,
+			config_at_1.clone(),
+		);
+		assert_eq!(
+			storage.configuration_at(&BlockId::Hash(block3)).unwrap().config,
+			config_at_3.clone(),
+		);
+		assert_eq!(
+			storage.configuration_at(&BlockId::Hash(block4)).unwrap().config,
+			config_at_3.clone(),
+		);
+		assert_eq!(
+			storage.configuration_at(&BlockId::Hash(block5)).unwrap().config,
+			config_at_5.clone(),
+		);
+		assert_eq!(
+			storage.configuration_at(&BlockId::Hash(block6)).unwrap().config,
+			config_at_5.clone(),
+		);
+		assert_eq!(
+			storage.configuration_at(&BlockId::Hash(block7)).unwrap().config,
+			config_at_7.clone(),
+		);
+	}
+
+	#[test]
+	fn test_finalize_several_configuration_change_blocks_in_single_operation() {
+		let mut backend = Backend::<Block>::new_test(10, 10);
+		backend.changes_tries_storage.min_blocks_to_keep = Some(8);
+
+		let configs = (0..=7).map(|i| Some(ChangesTrieConfiguration::new(2, i))).collect::<Vec<_>>();
+
+		// insert unfinalized headers
+		let block0 = insert_header_with_configuration_change(&backend, 0, Default::default(), None, configs[0].clone());
+		let block1 = insert_header_with_configuration_change(&backend, 1, block0, changes(1), configs[1].clone());
+		let block2 = insert_header_with_configuration_change(&backend, 2, block1, changes(2), configs[2].clone());
+
+		let side_config2_1 = Some(ChangesTrieConfiguration::new(3, 2));
+		let side_config2_2 = Some(ChangesTrieConfiguration::new(3, 3));
+		let block2_1 = insert_header_with_configuration_change(&backend, 2, block1, changes(8), side_config2_1.clone());
+		let _ = insert_header_with_configuration_change(&backend, 3, block2_1, changes(9), side_config2_2.clone());
+
+		// insert finalized header => 4 headers are finalized at once
+		let header3 = Header {
+			number: 3,
+			parent_hash: block2,
+			state_root: Default::default(),
+			digest: Digest {
+				logs: vec![
+					DigestItem::ChangesTrieSignal(ChangesTrieSignal::NewConfiguration(configs[3].clone())),
+				],
+			},
+			extrinsics_root: Default::default(),
+		};
+		let block3 = header3.hash();
+		let mut op = backend.begin_operation().unwrap();
+		backend.begin_state_operation(&mut op, BlockId::Hash(block2)).unwrap();
+		op.mark_finalized(BlockId::Hash(block1), None).unwrap();
+		op.mark_finalized(BlockId::Hash(block2), None).unwrap();
+		op.set_block_data(header3, None, None, NewBlockState::Final).unwrap();
+		backend.commit_operation(op).unwrap();
+
+		// insert more unfinalized headers
+		let block4 = insert_header_with_configuration_change(&backend, 4, block3, changes(4), configs[4].clone());
+		let block5 = insert_header_with_configuration_change(&backend, 5, block4, changes(5), configs[5].clone());
+		let block6 = insert_header_with_configuration_change(&backend, 6, block5, changes(6), configs[6].clone());
+
+		// insert finalized header => 4 headers are finalized at once
+		let header7 = Header {
+			number: 7,
+			parent_hash: block6,
+			state_root: Default::default(),
+			digest: Digest {
+				logs: vec![
+					DigestItem::ChangesTrieSignal(ChangesTrieSignal::NewConfiguration(configs[7].clone())),
+				],
+			},
+			extrinsics_root: Default::default(),
+		};
+		let mut op = backend.begin_operation().unwrap();
+		backend.begin_state_operation(&mut op, BlockId::Hash(block6)).unwrap();
+		op.mark_finalized(BlockId::Hash(block4), None).unwrap();
+		op.mark_finalized(BlockId::Hash(block5), None).unwrap();
+		op.mark_finalized(BlockId::Hash(block6), None).unwrap();
+		op.set_block_data(header7, None, None, NewBlockState::Final).unwrap();
+		backend.commit_operation(op).unwrap();
+	}
+
+	#[test]
+	fn changes_tries_configuration_is_reverted() {
+		let backend = Backend::<Block>::new_test(10, 10);
+
+		let config0 = Some(ChangesTrieConfiguration::new(2, 5));
+		let block0 = insert_header_with_configuration_change(&backend, 0, Default::default(), None, config0);
+		let config1 = Some(ChangesTrieConfiguration::new(2, 6));
+		let block1 = insert_header_with_configuration_change(&backend, 1, block0, changes(0), config1);
+		backend.finalize_block(BlockId::Number(1), Some(vec![42])).unwrap();
+		let config2 = Some(ChangesTrieConfiguration::new(2, 7));
+		let block2 = insert_header_with_configuration_change(&backend, 2, block1, changes(1), config2);
+		let config2_1 = Some(ChangesTrieConfiguration::new(2, 8));
+		let _ = insert_header_with_configuration_change(&backend, 3, block2, changes(10), config2_1);
+		let config2_2 = Some(ChangesTrieConfiguration::new(2, 9));
+		let block2_2 = insert_header_with_configuration_change(&backend, 3, block2, changes(20), config2_2);
+		let config2_3 = Some(ChangesTrieConfiguration::new(2, 10));
+		let _ = insert_header_with_configuration_change(&backend, 4, block2_2, changes(30), config2_3);
+
+		// before truncate there are 2 unfinalized forks - block2_1+block2_3
+		assert_eq!(
+			backend.changes_tries_storage.cache.0.write()
+				.get_cache(well_known_cache_keys::CHANGES_TRIE_CONFIG)
+				.unwrap()
+				.unfinalized()
+				.iter()
+				.map(|fork| fork.head().valid_from.number)
+				.collect::<Vec<_>>(),
+			vec![3, 4],
+		);
+
+		// after truncating block2_3 - there are 2 unfinalized forks - block2_1+block2_2
+		backend.revert(1, false).unwrap();
+		assert_eq!(
+			backend.changes_tries_storage.cache.0.write()
+				.get_cache(well_known_cache_keys::CHANGES_TRIE_CONFIG)
+				.unwrap()
+				.unfinalized()
+				.iter()
+				.map(|fork| fork.head().valid_from.number)
+				.collect::<Vec<_>>(),
+			vec![3, 3],
+		);
+
+		// after truncating block2_1 && block2_2 - there are still two unfinalized forks (cache impl specifics),
+		// the 1st one points to the block #3 because it isn't truncated
+		backend.revert(1, false).unwrap();
+		assert_eq!(
+			backend.changes_tries_storage.cache.0.write()
+				.get_cache(well_known_cache_keys::CHANGES_TRIE_CONFIG)
+				.unwrap()
+				.unfinalized()
+				.iter()
+				.map(|fork| fork.head().valid_from.number)
+				.collect::<Vec<_>>(),
+			vec![3, 2],
+		);
+
+		// after truncating block2 - there are no unfinalized forks
+		backend.revert(1, false).unwrap();
+		assert!(
+			backend.changes_tries_storage.cache.0.write()
+				.get_cache(well_known_cache_keys::CHANGES_TRIE_CONFIG)
+				.unwrap()
+				.unfinalized()
+				.iter()
+				.map(|fork| fork.head().valid_from.number)
+				.collect::<Vec<_>>()
+				.is_empty(),
+		);
+	}
+}
diff --git a/client/db/src/lib.rs b/client/db/src/lib.rs
index 06d0dc18ffa36..be569194972cc 100644
--- a/client/db/src/lib.rs
+++ b/client/db/src/lib.rs
@@ -31,18 +31,21 @@ pub mod offchain;
 
 mod children;
 mod cache;
+mod changes_tries_storage;
 mod storage_cache;
+#[cfg(any(feature = "kvdb-rocksdb", test))]
+mod upgrade;
 mod utils;
 mod stats;
 
 use std::sync::Arc;
 use std::path::PathBuf;
 use std::io;
-use std::collections::{HashMap, HashSet};
+use std::collections::HashMap;
 
 use sc_client_api::{execution_extensions::ExecutionExtensions, ForkBlocks, UsageInfo, MemoryInfo, BadBlocks, IoInfo};
 use sc_client_api::backend::NewBlockState;
-use sc_client_api::backend::{StorageCollection, ChildStorageCollection};
+use sc_client_api::backend::PrunableStateChangesTrieStorage;
 use sp_blockchain::{
 	Result as ClientResult, Error as ClientError,
 	well_known_cache_keys, HeaderBackend,
@@ -51,11 +54,11 @@ use codec::{Decode, Encode};
 use hash_db::Prefix;
 use kvdb::{KeyValueDB, DBTransaction};
 use sp_trie::{MemoryDB, PrefixedMemoryDB, prefixed_key};
-use parking_lot::{Mutex, RwLock};
-use sp_core::{ChangesTrieConfiguration, convert_hash, traits::CodeExecutor};
+use parking_lot::RwLock;
+use sp_core::{ChangesTrieConfiguration, traits::CodeExecutor};
 use sp_core::storage::{well_known_keys, ChildInfo};
 use sp_runtime::{
-	generic::{BlockId, DigestItem}, Justification, Storage,
+	generic::BlockId, Justification, Storage,
 	BuildStorage,
 };
 use sp_runtime::traits::{
@@ -63,10 +66,12 @@ use sp_runtime::traits::{
 };
 use sc_executor::RuntimeInfo;
 use sp_state_machine::{
-	DBValue, ChangesTrieTransaction, ChangesTrieCacheAction, ChangesTrieBuildCache,
-	backend::Backend as StateBackend, UsageInfo as StateUsageInfo,
+	DBValue, ChangesTrieTransaction, ChangesTrieCacheAction, UsageInfo as StateUsageInfo,
+	StorageCollection, ChildStorageCollection,
+	backend::Backend as StateBackend,
 };
-use crate::utils::{Meta, db_err, meta_keys, read_db, read_meta};
+use crate::utils::{DatabaseType, Meta, db_err, meta_keys, read_db, read_meta};
+use crate::changes_tries_storage::{DbChangesTrieStorage, DbChangesTrieStorageTransaction};
 use sc_client::leaves::{LeafSet, FinalizationDisplaced};
 use sc_state_db::StateDb;
 use sp_blockchain::{CachedHeaderMetadata, HeaderMetadata, HeaderMetadataCache};
@@ -274,7 +279,7 @@ pub enum DatabaseSettingsSrc {
 pub fn new_client<E, S, Block, RA>(
 	settings: DatabaseSettings,
 	executor: E,
-	genesis_storage: S,
+	genesis_storage: &S,
 	fork_blocks: ForkBlocks<Block>,
 	bad_blocks: BadBlocks<Block>,
 	execution_extensions: ExecutionExtensions<Block>,
@@ -322,6 +327,7 @@ pub(crate) mod columns {
 	pub const AUX: u32 = 8;
 	/// Offchain workers local storage
 	pub const OFFCHAIN: u32 = 9;
+	pub const CACHE: u32 = 10;
 }
 
 struct PendingBlock<Block: BlockT> {
@@ -352,7 +358,7 @@ pub struct BlockchainDb<Block: BlockT> {
 
 impl<Block: BlockT> BlockchainDb<Block> {
 	fn new(db: Arc<dyn KeyValueDB>) -> ClientResult<Self> {
-		let meta = read_meta::<Block>(&*db, columns::META, columns::HEADER)?;
+		let meta = read_meta::<Block>(&*db, columns::HEADER)?;
 		let leaves = LeafSet::read_from_db(&*db, columns::META, meta_keys::LEAF_PREFIX)?;
 		Ok(BlockchainDb {
 			db,
@@ -511,7 +517,8 @@ pub struct BlockImportOperation<Block: BlockT> {
 	storage_updates: StorageCollection,
 	child_storage_updates: ChildStorageCollection,
 	changes_trie_updates: MemoryDB<HasherFor<Block>>,
-	changes_trie_cache_update: Option<ChangesTrieCacheAction<Block::Hash, NumberFor<Block>>>,
+	changes_trie_build_cache_update: Option<ChangesTrieCacheAction<Block::Hash, NumberFor<Block>>>,
+	changes_trie_config_update: Option<Option<ChangesTrieConfiguration>>,
 	pending_block: Option<PendingBlock<Block>>,
 	aux_ops: Vec<(Vec<u8>, Option<Vec<u8>>)>,
 	finalized_blocks: Vec<(BlockId<Block>, Option<Justification>)>,
@@ -545,6 +552,9 @@ impl<Block: BlockT> sc_client_api::backend::BlockImportOperation<Block> for Bloc
 		leaf_state: NewBlockState,
 	) -> ClientResult<()> {
 		assert!(self.pending_block.is_none(), "Only one block per operation is allowed");
+		if let Some(changes_trie_config_update) = changes_tries_storage::extract_new_configuration(&header) {
+			self.changes_trie_config_update = Some(changes_trie_config_update.clone());
+		}
 		self.pending_block = Some(PendingBlock {
 			header,
 			body,
@@ -583,12 +593,22 @@ impl<Block: BlockT> sc_client_api::backend::BlockImportOperation<Block> for Bloc
 			child_content.data.into_iter().map(|(k, v)| (k, Some(v))), child_content.child_info),
 		);
 
+		let mut changes_trie_config: Option<ChangesTrieConfiguration> = None;
 		let (root, transaction) = self.old_state.full_storage_root(
-			storage.top.into_iter().map(|(k, v)| (k, Some(v))),
+			storage.top.into_iter().map(|(k, v)| {
+				if k == well_known_keys::CHANGES_TRIE_CONFIG {
+					changes_trie_config = Some(
+						Decode::decode(&mut &v[..])
+							.expect("changes trie configuration is encoded properly at genesis")
+					);
+				}
+				(k, Some(v))
+			}),
 			child_delta
 		);
 
 		self.db_updates = transaction;
+		self.changes_trie_config_update = Some(changes_trie_config);
 		self.commit_state = true;
 		Ok(root)
 	}
@@ -598,7 +618,7 @@ impl<Block: BlockT> sc_client_api::backend::BlockImportOperation<Block> for Bloc
 		update: ChangesTrieTransaction<HasherFor<Block>, NumberFor<Block>>,
 	) -> ClientResult<()> {
 		self.changes_trie_updates = update.0;
-		self.changes_trie_cache_update = Some(update.1);
+		self.changes_trie_build_cache_update = Some(update.1);
 		Ok(())
 	}
 
@@ -674,174 +694,6 @@ impl<Block: BlockT> sp_state_machine::Storage<HasherFor<Block>> for DbGenesisSto
 	}
 }
 
-/// A database wrapper for changes tries.
-pub struct DbChangesTrieStorage<Block: BlockT> {
-	db: Arc<dyn KeyValueDB>,
-	meta: Arc<RwLock<Meta<NumberFor<Block>, Block::Hash>>>,
-	min_blocks_to_keep: Option<u32>,
-	cache: RwLock<ChangesTrieBuildCache<Block::Hash, NumberFor<Block>>>,
-}
-
-impl<Block: BlockT> DbChangesTrieStorage<Block> {
-	/// Commit new changes trie.
-	pub fn commit(&self, tx: &mut DBTransaction, mut changes_trie: MemoryDB<HasherFor<Block>>) {
-		for (key, (val, _)) in changes_trie.drain() {
-			tx.put(columns::CHANGES_TRIE, key.as_ref(), &val);
-		}
-	}
-
-	/// Commit changes into changes trie build cache.
-	pub fn commit_cache(&self, cache_update: ChangesTrieCacheAction<Block::Hash, NumberFor<Block>>) {
-		self.cache.write().perform(cache_update);
-	}
-
-	/// Prune obsolete changes tries.
-	pub fn prune(
-		&self,
-		config: &ChangesTrieConfiguration,
-		tx: &mut DBTransaction,
-		block_hash: Block::Hash,
-		block_num: NumberFor<Block>,
-	) {
-		// never prune on archive nodes
-		let min_blocks_to_keep = match self.min_blocks_to_keep {
-			Some(min_blocks_to_keep) => min_blocks_to_keep,
-			None => return,
-		};
-
-		sp_state_machine::prune_changes_tries(
-			config,
-			&*self,
-			min_blocks_to_keep.into(),
-			&sp_state_machine::ChangesTrieAnchorBlockId {
-				hash: convert_hash(&block_hash),
-				number: block_num,
-			},
-			|node| tx.delete(columns::CHANGES_TRIE, node.as_ref()));
-	}
-}
-
-impl<Block: BlockT> sc_client_api::backend::PrunableStateChangesTrieStorage<Block>
-	for DbChangesTrieStorage<Block>
-{
-	fn oldest_changes_trie_block(
-		&self,
-		config: &ChangesTrieConfiguration,
-		best_finalized_block: NumberFor<Block>,
-	) -> NumberFor<Block> {
-		match self.min_blocks_to_keep {
-			Some(min_blocks_to_keep) => sp_state_machine::oldest_non_pruned_changes_trie(
-				config,
-				min_blocks_to_keep.into(),
-				best_finalized_block,
-			),
-			None => One::one(),
-		}
-	}
-}
-
-impl<Block: BlockT> sp_state_machine::ChangesTrieRootsStorage<HasherFor<Block>, NumberFor<Block>>
-	for DbChangesTrieStorage<Block>
-{
-	fn build_anchor(
-		&self,
-		hash: Block::Hash,
-	) -> Result<sp_state_machine::ChangesTrieAnchorBlockId<Block::Hash, NumberFor<Block>>, String> {
-		utils::read_header::<Block>(
-			&*self.db,
-			columns::KEY_LOOKUP,
-			columns::HEADER,
-			BlockId::Hash(hash),
-		)
-			.map_err(|e| e.to_string())
-			.and_then(|maybe_header| maybe_header.map(|header|
-				sp_state_machine::ChangesTrieAnchorBlockId {
-					hash,
-					number: *header.number(),
-				}
-			).ok_or_else(|| format!("Unknown header: {}", hash)))
-	}
-
-	fn root(
-		&self,
-		anchor: &sp_state_machine::ChangesTrieAnchorBlockId<Block::Hash, NumberFor<Block>>,
-		block: NumberFor<Block>,
-	) -> Result<Option<Block::Hash>, String> {
-		// check API requirement: we can't get NEXT block(s) based on anchor
-		if block > anchor.number {
-			return Err(
-				format!("Can't get changes trie root at {} using anchor at {}", block, anchor.number)
-			)
-		}
-
-		// we need to get hash of the block to resolve changes trie root
-		let block_id = if block <= self.meta.read().finalized_number {
-			// if block is finalized, we could just read canonical hash
-			BlockId::Number(block)
-		} else {
-			// the block is not finalized
-			let mut current_num = anchor.number;
-			let mut current_hash: Block::Hash = convert_hash(&anchor.hash);
-			let maybe_anchor_header: Block::Header = utils::require_header::<Block>(
-				&*self.db, columns::KEY_LOOKUP, columns::HEADER, BlockId::Number(current_num)
-			).map_err(|e| e.to_string())?;
-			if maybe_anchor_header.hash() == current_hash {
-				// if anchor is canonicalized, then the block is also canonicalized
-				BlockId::Number(block)
-			} else {
-				// else (block is not finalized + anchor is not canonicalized):
-				// => we should find the required block hash by traversing
-				// back from the anchor to the block with given number
-				while current_num != block {
-					let current_header: Block::Header = utils::require_header::<Block>(
-						&*self.db, columns::KEY_LOOKUP, columns::HEADER, BlockId::Hash(current_hash)
-					).map_err(|e| e.to_string())?;
-
-					current_hash = *current_header.parent_hash();
-					current_num = current_num - One::one();
-				}
-
-				BlockId::Hash(current_hash)
-			}
-		};
-
-		Ok(
-			utils::require_header::<Block>(
-				&*self.db,
-				columns::KEY_LOOKUP,
-				columns::HEADER,
-				block_id,
-			)
-			.map_err(|e| e.to_string())?
-			.digest()
-			.log(DigestItem::as_changes_trie_root)
-			.cloned()
-		)
-	}
-}
-
-impl<Block: BlockT> sp_state_machine::ChangesTrieStorage<HasherFor<Block>, NumberFor<Block>>
-	for DbChangesTrieStorage<Block>
-{
-	fn as_roots_storage(&self)
-		-> &dyn sp_state_machine::ChangesTrieRootsStorage<HasherFor<Block>, NumberFor<Block>>
-	{
-		self
-	}
-
-	fn with_cached_changed_keys(
-		&self,
-		root: &Block::Hash,
-		functor: &mut dyn FnMut(&HashMap<Option<Vec<u8>>, HashSet<Vec<u8>>>),
-	) -> bool {
-		self.cache.read().with_changed_keys(root, functor)
-	}
-
-	fn get(&self, key: &Block::Hash, _prefix: Prefix) -> Result<Option<DBValue>, String> {
-		self.db.get(columns::CHANGES_TRIE, key.as_ref()).map_err(|err| format!("{}", err))
-	}
-}
-
 /// Frozen `value` at time `at`.
 ///
 /// Used as inner structure under lock in `FrozenForDuration`.
@@ -889,9 +741,6 @@ pub struct Backend<Block: BlockT> {
 	storage: Arc<StorageDb<Block>>,
 	offchain_storage: offchain::LocalStorage,
 	changes_tries_storage: DbChangesTrieStorage<Block>,
-	/// None<*> means that the value hasn't been cached yet. Some(*) means that the value (either None or
-	/// Some(*)) has been cached and is valid.
-	changes_trie_config: Mutex<Option<Option<ChangesTrieConfiguration>>>,
 	blockchain: BlockchainDb<Block>,
 	canonicalization_delay: u64,
 	shared_cache: SharedCache<Block>,
@@ -906,7 +755,7 @@ impl<Block: BlockT> Backend<Block> {
 	///
 	/// The pruning window is how old a block must be before the state is pruned.
 	pub fn new(config: DatabaseSettings, canonicalization_delay: u64) -> ClientResult<Self> {
-		let db = crate::utils::open_database(&config, columns::META, "full")?;
+		let db = crate::utils::open_database::<Block>(&config, DatabaseType::Full)?;
 		Self::from_kvdb(db as Arc<_>, canonicalization_delay, &config)
 	}
 
@@ -942,22 +791,25 @@ impl<Block: BlockT> Backend<Block> {
 			state_db,
 		};
 		let offchain_storage = offchain::LocalStorage::new(db.clone());
-		let changes_tries_storage = DbChangesTrieStorage {
+		let changes_tries_storage = DbChangesTrieStorage::new(
 			db,
+			columns::META,
+			columns::CHANGES_TRIE,
+			columns::KEY_LOOKUP,
+			columns::HEADER,
+			columns::CACHE,
 			meta,
-			min_blocks_to_keep: if is_archive_pruning {
+			if is_archive_pruning {
 				None
 			} else {
 				Some(MIN_BLOCKS_TO_KEEP_CHANGES_TRIES_FOR)
 			},
-			cache: RwLock::new(ChangesTrieBuildCache::new()),
-		};
+		)?;
 
 		Ok(Backend {
 			storage: Arc::new(storage_db),
 			offchain_storage,
 			changes_tries_storage,
-			changes_trie_config: Mutex::new(None),
 			blockchain,
 			canonicalization_delay,
 			shared_cache: new_shared_cache(
@@ -1026,26 +878,6 @@ impl<Block: BlockT> Backend<Block> {
 		self.blockchain.db.iter(columns::HEADER).count() as u64
 	}
 
-	/// Read (from storage or cache) changes trie config.
-	///
-	/// Currently changes tries configuration is set up once (at genesis) and could not
-	/// be changed. Thus, we'll actually read value once and then just use cached value.
-	fn changes_trie_config(&self, block: Block::Hash) -> ClientResult<Option<ChangesTrieConfiguration>> {
-		let mut cached_changes_trie_config = self.changes_trie_config.lock();
-		match cached_changes_trie_config.clone() {
-			Some(cached_changes_trie_config) => Ok(cached_changes_trie_config),
-			None => {
-				use sc_client_api::backend::Backend;
-				let changes_trie_config = self
-					.state_at(BlockId::Hash(block))?
-					.storage(well_known_keys::CHANGES_TRIE_CONFIG)?
-					.and_then(|v| Decode::decode(&mut &*v).ok());
-				*cached_changes_trie_config = Some(changes_trie_config.clone());
-				Ok(changes_trie_config)
-			},
-		}
-	}
-
 	/// Handle setting head within a transaction. `route_to` should be the last
 	/// block that existed in the database. `best_to` should be the best block
 	/// to be set.
@@ -1137,6 +969,7 @@ impl<Block: BlockT> Backend<Block> {
 		header: &Block::Header,
 		last_finalized: Option<Block::Hash>,
 		justification: Option<Justification>,
+		changes_trie_cache_ops: &mut Option<DbChangesTrieStorageTransaction<Block>>,
 		finalization_displaced: &mut Option<FinalizationDisplaced<Block::Hash, NumberFor<Block>>>,
 	) -> ClientResult<(Block::Hash, <Block::Header as HeaderT>::Number, bool, bool)> {
 		// TODO: ensure best chain contains this block.
@@ -1144,8 +977,10 @@ impl<Block: BlockT> Backend<Block> {
 		self.ensure_sequential_finalization(header, last_finalized)?;
 		self.note_finalized(
 			transaction,
+			false,
 			header,
 			*hash,
+			changes_trie_cache_ops,
 			finalization_displaced,
 		)?;
 
@@ -1204,6 +1039,7 @@ impl<Block: BlockT> Backend<Block> {
 		let mut meta_updates = Vec::with_capacity(operation.finalized_blocks.len());
 		let mut last_finalized_hash = self.blockchain.meta.read().finalized_hash;
 
+		let mut changes_trie_cache_ops = None;
 		for (block, justification) in operation.finalized_blocks {
 			let block_hash = self.blockchain.expect_block_hash_from_id(&block)?;
 			let block_header = self.blockchain.expect_header(BlockId::Hash(block_hash))?;
@@ -1214,6 +1050,7 @@ impl<Block: BlockT> Backend<Block> {
 				&block_header,
 				Some(last_finalized_hash),
 				justification,
+				&mut changes_trie_cache_ops,
 				&mut finalization_displaced_leaves,
 			)?);
 			last_finalized_hash = block_hash;
@@ -1257,6 +1094,11 @@ impl<Block: BlockT> Backend<Block> {
 			if number.is_zero() {
 				transaction.put(columns::META, meta_keys::FINALIZED_BLOCK, &lookup_key);
 				transaction.put(columns::META, meta_keys::GENESIS_HASH, hash.as_ref());
+
+				// for tests, because config is set from within the reset_storage
+				if operation.changes_trie_config_update.is_none() {
+					operation.changes_trie_config_update = Some(None);
+				}
 			}
 
 			let finalized = if operation.commit_state {
@@ -1293,8 +1135,21 @@ impl<Block: BlockT> Backend<Block> {
 			let header = &pending_block.header;
 			let is_best = pending_block.leaf_state.is_best();
 			let changes_trie_updates = operation.changes_trie_updates;
-
-			self.changes_tries_storage.commit(&mut transaction, changes_trie_updates);
+			let changes_trie_config_update = operation.changes_trie_config_update;
+			changes_trie_cache_ops = Some(self.changes_tries_storage.commit(
+				&mut transaction,
+				changes_trie_updates,
+				cache::ComplexBlockId::new(
+					*header.parent_hash(),
+					if number.is_zero() { Zero::zero() } else { number - One::one() },
+				),
+				cache::ComplexBlockId::new(hash, number),
+				header,
+				finalized,
+				changes_trie_config_update,
+				changes_trie_cache_ops,
+			)?);
+			self.state_usage.merge_sm(operation.old_state.usage_info());
 			let cache = operation.old_state.release(); // release state reference so that it can be finalized
 
 			if finalized {
@@ -1302,8 +1157,10 @@ impl<Block: BlockT> Backend<Block> {
 				self.ensure_sequential_finalization(header, Some(last_finalized_hash))?;
 				self.note_finalized(
 					&mut transaction,
+					true,
 					header,
 					hash,
+					&mut changes_trie_cache_ops,
 					&mut finalization_displaced_leaves,
 				)?;
 			} else {
@@ -1353,11 +1210,15 @@ impl<Block: BlockT> Backend<Block> {
 
 		let write_result = self.storage.db.write(transaction).map_err(db_err);
 
-		if let Some(changes_trie_cache_update) = operation.changes_trie_cache_update {
-			self.changes_tries_storage.commit_cache(changes_trie_cache_update);
-		}
-
-		if let Some((number, hash, enacted, retracted, displaced_leaf, is_best, mut cache)) = imported {
+		if let Some((
+			number,
+			hash,
+			enacted,
+			retracted,
+			displaced_leaf,
+			is_best,
+			mut cache,
+		)) = imported {
 			if let Err(e) = write_result {
 				let mut leaves = self.blockchain.leaves.write();
 				let mut undo = leaves.undo();
@@ -1383,6 +1244,11 @@ impl<Block: BlockT> Backend<Block> {
 			);
 		}
 
+		if let Some(changes_trie_build_cache_update) = operation.changes_trie_build_cache_update {
+			self.changes_tries_storage.commit_build_cache(changes_trie_build_cache_update);
+		}
+		self.changes_tries_storage.post_commit(changes_trie_cache_ops);
+
 		if let Some((enacted, retracted)) = cache_update {
 			self.shared_cache.lock().sync(&enacted, &retracted);
 		}
@@ -1401,15 +1267,15 @@ impl<Block: BlockT> Backend<Block> {
 	fn note_finalized(
 		&self,
 		transaction: &mut DBTransaction,
+		is_inserted: bool,
 		f_header: &Block::Header,
 		f_hash: Block::Hash,
+		changes_trie_cache_ops: &mut Option<DbChangesTrieStorageTransaction<Block>>,
 		displaced: &mut Option<FinalizationDisplaced<Block::Hash, NumberFor<Block>>>
 	) -> ClientResult<()> {
 		let f_num = f_header.number().clone();
 
 		if self.storage.state_db.best_canonical().map(|c| f_num.saturated_into::<u64>() > c).unwrap_or(true) {
-			let parent_hash = f_header.parent_hash().clone();
-
 			let lookup_key = utils::number_and_hash_to_lookup_key(f_num, f_hash.clone())?;
 			transaction.put(columns::META, meta_keys::FINALIZED_BLOCK, &lookup_key);
 
@@ -1417,9 +1283,16 @@ impl<Block: BlockT> Backend<Block> {
 				.map_err(|e: sc_state_db::Error<io::Error>| sp_blockchain::Error::from(format!("State database error: {:?}", e)))?;
 			apply_state_commit(transaction, commit);
 
-			let changes_trie_config = self.changes_trie_config(parent_hash)?;
-			if let Some(changes_trie_config) = changes_trie_config {
-				self.changes_tries_storage.prune(&changes_trie_config, transaction, f_hash, f_num);
+			if !f_num.is_zero() {
+				let new_changes_trie_cache_ops = self.changes_tries_storage.finalize(
+					transaction,
+					*f_header.parent_hash(),
+					f_hash,
+					f_num,
+					if is_inserted { Some(&f_header) } else { None },
+					changes_trie_cache_ops.take(),
+				)?;
+				*changes_trie_cache_ops = Some(new_changes_trie_cache_ops);
 			}
 		}
 
@@ -1476,7 +1349,6 @@ impl<Block: BlockT> sc_client_api::backend::Backend<Block> for Backend<Block> {
 	type BlockImportOperation = BlockImportOperation<Block>;
 	type Blockchain = BlockchainDb<Block>;
 	type State = CachingState<RefTrackingState<Block>, Block>;
-	type ChangesTrieStorage = DbChangesTrieStorage<Block>;
 	type OffchainStorage = offchain::LocalStorage;
 
 	fn begin_operation(&self) -> ClientResult<Self::BlockImportOperation> {
@@ -1487,8 +1359,9 @@ impl<Block: BlockT> sc_client_api::backend::Backend<Block> for Backend<Block> {
 			db_updates: PrefixedMemoryDB::default(),
 			storage_updates: Default::default(),
 			child_storage_updates: Default::default(),
+			changes_trie_config_update: None,
 			changes_trie_updates: MemoryDB::default(),
-			changes_trie_cache_update: None,
+			changes_trie_build_cache_update: None,
 			aux_ops: Vec::new(),
 			finalized_blocks: Vec::new(),
 			set_head: None,
@@ -1532,16 +1405,19 @@ impl<Block: BlockT> sc_client_api::backend::Backend<Block> for Backend<Block> {
 		let header = self.blockchain.expect_header(block)?;
 		let mut displaced = None;
 		let commit = |displaced| {
+			let mut changes_trie_cache_ops = None;
 			let (hash, number, is_best, is_finalized) = self.finalize_block_with_transaction(
 				&mut transaction,
 				&hash,
 				&header,
 				None,
 				justification,
+				&mut changes_trie_cache_ops,
 				displaced,
 			)?;
 			self.storage.db.write(transaction).map_err(db_err)?;
 			self.blockchain.update_meta(hash, number, is_best, is_finalized);
+			self.changes_tries_storage.post_commit(changes_trie_cache_ops);
 			Ok(())
 		};
 		match commit(&mut displaced) {
@@ -1557,7 +1433,7 @@ impl<Block: BlockT> sc_client_api::backend::Backend<Block> for Backend<Block> {
 		Ok(())
 	}
 
-	fn changes_trie_storage(&self) -> Option<&Self::ChangesTrieStorage> {
+	fn changes_trie_storage(&self) -> Option<&dyn PrunableStateChangesTrieStorage<Block>> {
 		Some(&self.changes_tries_storage)
 	}
 
@@ -1616,6 +1492,7 @@ impl<Block: BlockT> sc_client_api::backend::Backend<Block> for Backend<Block> {
 				match self.storage.state_db.revert_one() {
 					Some(commit) => {
 						apply_state_commit(&mut transaction, commit);
+						let removed_number = best_number;
 						let removed = self.blockchain.header(BlockId::Number(best_number))?.ok_or_else(
 							|| sp_blockchain::Error::UnknownBlock(
 								format!("Error reverting to {}. Block hash not found.", best_number)))?;
@@ -1628,6 +1505,13 @@ impl<Block: BlockT> sc_client_api::backend::Backend<Block> for Backend<Block> {
 						let update_finalized = best_number < finalized;
 
 						let key = utils::number_and_hash_to_lookup_key(best_number.clone(), &best_hash)?;
+						let changes_trie_cache_ops = self.changes_tries_storage.revert(
+							&mut transaction,
+							&cache::ComplexBlockId::new(
+								removed.hash(),
+								removed_number,
+							),
+						)?;
 						transaction.put(columns::META, meta_keys::BEST_BLOCK, &key);
 						if update_finalized {
 							transaction.put(columns::META, meta_keys::FINALIZED_BLOCK, &key);
@@ -1635,6 +1519,7 @@ impl<Block: BlockT> sc_client_api::backend::Backend<Block> for Backend<Block> {
 						transaction.delete(columns::KEY_LOOKUP, removed.hash().as_ref());
 						children::remove_children(&mut transaction, columns::META, meta_keys::CHILDREN_PREFIX, best_hash);
 						self.storage.db.write(transaction).map_err(db_err)?;
+						self.changes_tries_storage.post_commit(Some(changes_trie_cache_ops));
 						self.blockchain.update_meta(best_hash, best_number, true, update_finalized);
 					}
 					None => return Ok(c.saturated_into::<NumberFor<Block>>())
@@ -1735,6 +1620,7 @@ impl<Block: BlockT> sc_client_api::backend::Backend<Block> for Backend<Block> {
 	}
 
 	fn destroy_state(&self, state: Self::State) -> ClientResult<()> {
+		self.state_usage.merge_sm(state.usage_info());
 		if let Some(hash) = state.cache.parent_hash.clone() {
 			let is_best = self.blockchain.meta.read().best_hash == hash;
 			state.release().sync_cache(&[], &[], vec![], vec![], None, None, is_best);
@@ -1749,14 +1635,8 @@ impl<Block: BlockT> sc_client_api::backend::Backend<Block> for Backend<Block> {
 
 impl<Block: BlockT> sc_client_api::backend::LocalBackend<Block> for Backend<Block> {}
 
-/// TODO: remove me in #3201
-pub fn unused_sink<Block: BlockT>(cache_tx: crate::cache::DbCacheTransaction<Block>) {
-	cache_tx.on_block_revert(&crate::cache::ComplexBlockId::new(Default::default(), 0.into())).unwrap();
-	unimplemented!()
-}
-
 #[cfg(test)]
-mod tests {
+pub(crate) mod tests {
 	use hash_db::{HashDB, EMPTY_PREFIX};
 	use super::*;
 	use crate::columns;
@@ -1765,12 +1645,13 @@ mod tests {
 	use sc_client::blockchain::Backend as BLBTrait;
 	use sp_runtime::testing::{Header, Block as RawBlock, ExtrinsicWrapper};
 	use sp_runtime::traits::{Hash, BlakeTwo256};
-	use sp_state_machine::{TrieMut, TrieDBMut, ChangesTrieRootsStorage, ChangesTrieStorage};
+	use sp_runtime::generic::DigestItem;
+	use sp_state_machine::{TrieMut, TrieDBMut};
 	use sp_blockchain::{lowest_common_ancestor, tree_route};
 
-	type Block = RawBlock<ExtrinsicWrapper<u64>>;
+	pub(crate) type Block = RawBlock<ExtrinsicWrapper<u64>>;
 
-	fn prepare_changes(changes: Vec<(Vec<u8>, Vec<u8>)>) -> (H256, MemoryDB<Blake2Hasher>) {
+	pub fn prepare_changes(changes: Vec<(Vec<u8>, Vec<u8>)>) -> (H256, MemoryDB<Blake2Hasher>) {
 		let mut changes_root = H256::default();
 		let mut changes_trie_update = MemoryDB::<Blake2Hasher>::default();
 		{
@@ -1786,20 +1667,22 @@ mod tests {
 		(changes_root, changes_trie_update)
 	}
 
-	fn insert_header(
+	pub fn insert_header(
 		backend: &Backend<Block>,
 		number: u64,
 		parent_hash: H256,
-		changes: Vec<(Vec<u8>, Vec<u8>)>,
+		changes: Option<Vec<(Vec<u8>, Vec<u8>)>>,
 		extrinsics_root: H256,
 	) -> H256 {
 		use sp_runtime::testing::Digest;
-		let (changes_root, changes_trie_update) = prepare_changes(changes);
-		let digest = Digest {
-			logs: vec![
-				DigestItem::ChangesTrieRoot(changes_root),
-			],
-		};
+
+		let mut digest = Digest::default();
+		let mut changes_trie_update = Default::default();
+		if let Some(changes) = changes {
+			let (root, update) = prepare_changes(changes);
+			digest.push(DigestItem::ChangesTrieRoot(root));
+			changes_trie_update = update;
+		}
 		let header = Header {
 			number,
 			parent_hash,
@@ -2126,238 +2009,20 @@ mod tests {
 		).unwrap().is_none());
 	}
 
-	#[test]
-	fn changes_trie_storage_works() {
-		let backend = Backend::<Block>::new_test(1000, 100);
-		backend.changes_tries_storage.meta.write().finalized_number = 1000;
-
-
-		let check_changes = |backend: &Backend<Block>, block: u64, changes: Vec<(Vec<u8>, Vec<u8>)>| {
-			let (changes_root, mut changes_trie_update) = prepare_changes(changes);
-			let anchor = sp_state_machine::ChangesTrieAnchorBlockId {
-				hash: backend.blockchain().header(BlockId::Number(block)).unwrap().unwrap().hash(),
-				number: block
-			};
-			assert_eq!(backend.changes_tries_storage.root(&anchor, block), Ok(Some(changes_root)));
-
-			for (key, (val, _)) in changes_trie_update.drain() {
-				assert_eq!(backend.changes_trie_storage().unwrap().get(&key, EMPTY_PREFIX), Ok(Some(val)));
-			}
-		};
-
-		let changes0 = vec![(b"key_at_0".to_vec(), b"val_at_0".to_vec())];
-		let changes1 = vec![
-			(b"key_at_1".to_vec(), b"val_at_1".to_vec()),
-			(b"another_key_at_1".to_vec(), b"another_val_at_1".to_vec()),
-		];
-		let changes2 = vec![(b"key_at_2".to_vec(), b"val_at_2".to_vec())];
-
-		let block0 = insert_header(&backend, 0, Default::default(), changes0.clone(), Default::default());
-		let block1 = insert_header(&backend, 1, block0, changes1.clone(), Default::default());
-		let _ = insert_header(&backend, 2, block1, changes2.clone(), Default::default());
-
-		// check that the storage contains tries for all blocks
-		check_changes(&backend, 0, changes0);
-		check_changes(&backend, 1, changes1);
-		check_changes(&backend, 2, changes2);
-	}
-
-	#[test]
-	fn changes_trie_storage_works_with_forks() {
-		let backend = Backend::<Block>::new_test(1000, 100);
-
-		let changes0 = vec![(b"k0".to_vec(), b"v0".to_vec())];
-		let changes1 = vec![(b"k1".to_vec(), b"v1".to_vec())];
-		let changes2 = vec![(b"k2".to_vec(), b"v2".to_vec())];
-		let block0 = insert_header(&backend, 0, Default::default(), changes0.clone(), Default::default());
-		let block1 = insert_header(&backend, 1, block0, changes1.clone(), Default::default());
-		let block2 = insert_header(&backend, 2, block1, changes2.clone(), Default::default());
-
-		let changes2_1_0 = vec![(b"k3".to_vec(), b"v3".to_vec())];
-		let changes2_1_1 = vec![(b"k4".to_vec(), b"v4".to_vec())];
-		let block2_1_0 = insert_header(&backend, 3, block2, changes2_1_0.clone(), Default::default());
-		let block2_1_1 = insert_header(&backend, 4, block2_1_0, changes2_1_1.clone(), Default::default());
-
-		let changes2_2_0 = vec![(b"k5".to_vec(), b"v5".to_vec())];
-		let changes2_2_1 = vec![(b"k6".to_vec(), b"v6".to_vec())];
-		let block2_2_0 = insert_header(&backend, 3, block2, changes2_2_0.clone(), Default::default());
-		let block2_2_1 = insert_header(&backend, 4, block2_2_0, changes2_2_1.clone(), Default::default());
-
-		// finalize block1
-		backend.changes_tries_storage.meta.write().finalized_number = 1;
-
-		// branch1: when asking for finalized block hash
-		let (changes1_root, _) = prepare_changes(changes1);
-		let anchor = sp_state_machine::ChangesTrieAnchorBlockId { hash: block2_1_1, number: 4 };
-		assert_eq!(backend.changes_tries_storage.root(&anchor, 1), Ok(Some(changes1_root)));
-
-		// branch2: when asking for finalized block hash
-		let anchor = sp_state_machine::ChangesTrieAnchorBlockId { hash: block2_2_1, number: 4 };
-		assert_eq!(backend.changes_tries_storage.root(&anchor, 1), Ok(Some(changes1_root)));
-
-		// branch1: when asking for non-finalized block hash (search by traversal)
-		let (changes2_1_0_root, _) = prepare_changes(changes2_1_0);
-		let anchor = sp_state_machine::ChangesTrieAnchorBlockId { hash: block2_1_1, number: 4 };
-		assert_eq!(backend.changes_tries_storage.root(&anchor, 3), Ok(Some(changes2_1_0_root)));
-
-		// branch2: when asking for non-finalized block hash (search using canonicalized hint)
-		let (changes2_2_0_root, _) = prepare_changes(changes2_2_0);
-		let anchor = sp_state_machine::ChangesTrieAnchorBlockId { hash: block2_2_1, number: 4 };
-		assert_eq!(backend.changes_tries_storage.root(&anchor, 3), Ok(Some(changes2_2_0_root)));
-
-		// finalize first block of branch2 (block2_2_0)
-		backend.changes_tries_storage.meta.write().finalized_number = 3;
-
-		// branch2: when asking for finalized block of this branch
-		assert_eq!(backend.changes_tries_storage.root(&anchor, 3), Ok(Some(changes2_2_0_root)));
-
-		// branch1: when asking for finalized block of other branch
-		// => result is incorrect (returned for the block of branch1), but this is expected,
-		// because the other fork is abandoned (forked before finalized header)
-		let anchor = sp_state_machine::ChangesTrieAnchorBlockId { hash: block2_1_1, number: 4 };
-		assert_eq!(backend.changes_tries_storage.root(&anchor, 3), Ok(Some(changes2_2_0_root)));
-	}
-
-	#[test]
-	fn changes_tries_with_digest_are_pruned_on_finalization() {
-		let mut backend = Backend::<Block>::new_test(1000, 100);
-		backend.changes_tries_storage.min_blocks_to_keep = Some(8);
-		let config = ChangesTrieConfiguration {
-			digest_interval: 2,
-			digest_levels: 2,
-		};
-
-		// insert some blocks
-		let block0 = insert_header(&backend, 0, Default::default(), vec![(b"key_at_0".to_vec(), b"val_at_0".to_vec())], Default::default());
-		let block1 = insert_header(&backend, 1, block0, vec![(b"key_at_1".to_vec(), b"val_at_1".to_vec())], Default::default());
-		let block2 = insert_header(&backend, 2, block1, vec![(b"key_at_2".to_vec(), b"val_at_2".to_vec())], Default::default());
-		let block3 = insert_header(&backend, 3, block2, vec![(b"key_at_3".to_vec(), b"val_at_3".to_vec())], Default::default());
-		let block4 = insert_header(&backend, 4, block3, vec![(b"key_at_4".to_vec(), b"val_at_4".to_vec())], Default::default());
-		let block5 = insert_header(&backend, 5, block4, vec![(b"key_at_5".to_vec(), b"val_at_5".to_vec())], Default::default());
-		let block6 = insert_header(&backend, 6, block5, vec![(b"key_at_6".to_vec(), b"val_at_6".to_vec())], Default::default());
-		let block7 = insert_header(&backend, 7, block6, vec![(b"key_at_7".to_vec(), b"val_at_7".to_vec())], Default::default());
-		let block8 = insert_header(&backend, 8, block7, vec![(b"key_at_8".to_vec(), b"val_at_8".to_vec())], Default::default());
-		let block9 = insert_header(&backend, 9, block8, vec![(b"key_at_9".to_vec(), b"val_at_9".to_vec())], Default::default());
-		let block10 = insert_header(&backend, 10, block9, vec![(b"key_at_10".to_vec(), b"val_at_10".to_vec())], Default::default());
-		let block11 = insert_header(&backend, 11, block10, vec![(b"key_at_11".to_vec(), b"val_at_11".to_vec())], Default::default());
-		let block12 = insert_header(&backend, 12, block11, vec![(b"key_at_12".to_vec(), b"val_at_12".to_vec())], Default::default());
-		let block13 = insert_header(&backend, 13, block12, vec![(b"key_at_13".to_vec(), b"val_at_13".to_vec())], Default::default());
-		backend.changes_tries_storage.meta.write().finalized_number = 13;
-
-		// check that roots of all tries are in the columns::CHANGES_TRIE
-		let anchor = sp_state_machine::ChangesTrieAnchorBlockId { hash: block13, number: 13 };
-		fn read_changes_trie_root(backend: &Backend<Block>, num: u64) -> H256 {
-			backend.blockchain().header(BlockId::Number(num)).unwrap().unwrap().digest().logs().iter()
-				.find(|i| i.as_changes_trie_root().is_some()).unwrap().as_changes_trie_root().unwrap().clone()
-		}
-		let root1 = read_changes_trie_root(&backend, 1); assert_eq!(backend.changes_tries_storage.root(&anchor, 1).unwrap(), Some(root1));
-		let root2 = read_changes_trie_root(&backend, 2); assert_eq!(backend.changes_tries_storage.root(&anchor, 2).unwrap(), Some(root2));
-		let root3 = read_changes_trie_root(&backend, 3); assert_eq!(backend.changes_tries_storage.root(&anchor, 3).unwrap(), Some(root3));
-		let root4 = read_changes_trie_root(&backend, 4); assert_eq!(backend.changes_tries_storage.root(&anchor, 4).unwrap(), Some(root4));
-		let root5 = read_changes_trie_root(&backend, 5); assert_eq!(backend.changes_tries_storage.root(&anchor, 5).unwrap(), Some(root5));
-		let root6 = read_changes_trie_root(&backend, 6); assert_eq!(backend.changes_tries_storage.root(&anchor, 6).unwrap(), Some(root6));
-		let root7 = read_changes_trie_root(&backend, 7); assert_eq!(backend.changes_tries_storage.root(&anchor, 7).unwrap(), Some(root7));
-		let root8 = read_changes_trie_root(&backend, 8); assert_eq!(backend.changes_tries_storage.root(&anchor, 8).unwrap(), Some(root8));
-		let root9 = read_changes_trie_root(&backend, 9); assert_eq!(backend.changes_tries_storage.root(&anchor, 9).unwrap(), Some(root9));
-		let root10 = read_changes_trie_root(&backend, 10); assert_eq!(backend.changes_tries_storage.root(&anchor, 10).unwrap(), Some(root10));
-		let root11 = read_changes_trie_root(&backend, 11); assert_eq!(backend.changes_tries_storage.root(&anchor, 11).unwrap(), Some(root11));
-		let root12 = read_changes_trie_root(&backend, 12); assert_eq!(backend.changes_tries_storage.root(&anchor, 12).unwrap(), Some(root12));
-
-		// now simulate finalization of block#12, causing prune of tries at #1..#4
-		let mut tx = DBTransaction::new();
-		backend.changes_tries_storage.prune(&config, &mut tx, Default::default(), 12);
-		backend.storage.db.write(tx).unwrap();
-		assert!(backend.changes_tries_storage.get(&root1, EMPTY_PREFIX).unwrap().is_none());
-		assert!(backend.changes_tries_storage.get(&root2, EMPTY_PREFIX).unwrap().is_none());
-		assert!(backend.changes_tries_storage.get(&root3, EMPTY_PREFIX).unwrap().is_none());
-		assert!(backend.changes_tries_storage.get(&root4, EMPTY_PREFIX).unwrap().is_none());
-		assert!(backend.changes_tries_storage.get(&root5, EMPTY_PREFIX).unwrap().is_some());
-		assert!(backend.changes_tries_storage.get(&root6, EMPTY_PREFIX).unwrap().is_some());
-		assert!(backend.changes_tries_storage.get(&root7, EMPTY_PREFIX).unwrap().is_some());
-		assert!(backend.changes_tries_storage.get(&root8, EMPTY_PREFIX).unwrap().is_some());
-
-		// now simulate finalization of block#16, causing prune of tries at #5..#8
-		let mut tx = DBTransaction::new();
-		backend.changes_tries_storage.prune(&config, &mut tx, Default::default(), 16);
-		backend.storage.db.write(tx).unwrap();
-		assert!(backend.changes_tries_storage.get(&root5, EMPTY_PREFIX).unwrap().is_none());
-		assert!(backend.changes_tries_storage.get(&root6, EMPTY_PREFIX).unwrap().is_none());
-		assert!(backend.changes_tries_storage.get(&root7, EMPTY_PREFIX).unwrap().is_none());
-		assert!(backend.changes_tries_storage.get(&root8, EMPTY_PREFIX).unwrap().is_none());
-
-		// now "change" pruning mode to archive && simulate finalization of block#20
-		// => no changes tries are pruned, because we never prune in archive mode
-		backend.changes_tries_storage.min_blocks_to_keep = None;
-		let mut tx = DBTransaction::new();
-		backend.changes_tries_storage.prune(&config, &mut tx, Default::default(), 20);
-		backend.storage.db.write(tx).unwrap();
-		assert!(backend.changes_tries_storage.get(&root9, EMPTY_PREFIX).unwrap().is_some());
-		assert!(backend.changes_tries_storage.get(&root10, EMPTY_PREFIX).unwrap().is_some());
-		assert!(backend.changes_tries_storage.get(&root11, EMPTY_PREFIX).unwrap().is_some());
-		assert!(backend.changes_tries_storage.get(&root12, EMPTY_PREFIX).unwrap().is_some());
-	}
-
-	#[test]
-	fn changes_tries_without_digest_are_pruned_on_finalization() {
-		let mut backend = Backend::<Block>::new_test(1000, 100);
-		backend.changes_tries_storage.min_blocks_to_keep = Some(4);
-		let config = ChangesTrieConfiguration {
-			digest_interval: 0,
-			digest_levels: 0,
-		};
-
-		// insert some blocks
-		let block0 = insert_header(&backend, 0, Default::default(), vec![(b"key_at_0".to_vec(), b"val_at_0".to_vec())], Default::default());
-		let block1 = insert_header(&backend, 1, block0, vec![(b"key_at_1".to_vec(), b"val_at_1".to_vec())], Default::default());
-		let block2 = insert_header(&backend, 2, block1, vec![(b"key_at_2".to_vec(), b"val_at_2".to_vec())], Default::default());
-		let block3 = insert_header(&backend, 3, block2, vec![(b"key_at_3".to_vec(), b"val_at_3".to_vec())], Default::default());
-		let block4 = insert_header(&backend, 4, block3, vec![(b"key_at_4".to_vec(), b"val_at_4".to_vec())], Default::default());
-		let block5 = insert_header(&backend, 5, block4, vec![(b"key_at_5".to_vec(), b"val_at_5".to_vec())], Default::default());
-		let block6 = insert_header(&backend, 6, block5, vec![(b"key_at_6".to_vec(), b"val_at_6".to_vec())], Default::default());
-
-		// check that roots of all tries are in the columns::CHANGES_TRIE
-		let anchor = sp_state_machine::ChangesTrieAnchorBlockId { hash: block6, number: 6 };
-		fn read_changes_trie_root(backend: &Backend<Block>, num: u64) -> H256 {
-			backend.blockchain().header(BlockId::Number(num)).unwrap().unwrap().digest().logs().iter()
-				.find(|i| i.as_changes_trie_root().is_some()).unwrap().as_changes_trie_root().unwrap().clone()
-		}
-
-		let root1 = read_changes_trie_root(&backend, 1); assert_eq!(backend.changes_tries_storage.root(&anchor, 1).unwrap(), Some(root1));
-		let root2 = read_changes_trie_root(&backend, 2); assert_eq!(backend.changes_tries_storage.root(&anchor, 2).unwrap(), Some(root2));
-		let root3 = read_changes_trie_root(&backend, 3); assert_eq!(backend.changes_tries_storage.root(&anchor, 3).unwrap(), Some(root3));
-		let root4 = read_changes_trie_root(&backend, 4); assert_eq!(backend.changes_tries_storage.root(&anchor, 4).unwrap(), Some(root4));
-		let root5 = read_changes_trie_root(&backend, 5); assert_eq!(backend.changes_tries_storage.root(&anchor, 5).unwrap(), Some(root5));
-		let root6 = read_changes_trie_root(&backend, 6); assert_eq!(backend.changes_tries_storage.root(&anchor, 6).unwrap(), Some(root6));
-
-		// now simulate finalization of block#5, causing prune of trie at #1
-		let mut tx = DBTransaction::new();
-		backend.changes_tries_storage.prune(&config, &mut tx, block5, 5);
-		backend.storage.db.write(tx).unwrap();
-		assert!(backend.changes_tries_storage.get(&root1, EMPTY_PREFIX).unwrap().is_none());
-		assert!(backend.changes_tries_storage.get(&root2, EMPTY_PREFIX).unwrap().is_some());
-
-		// now simulate finalization of block#6, causing prune of tries at #2
-		let mut tx = DBTransaction::new();
-		backend.changes_tries_storage.prune(&config, &mut tx, block6, 6);
-		backend.storage.db.write(tx).unwrap();
-		assert!(backend.changes_tries_storage.get(&root2, EMPTY_PREFIX).unwrap().is_none());
-		assert!(backend.changes_tries_storage.get(&root3, EMPTY_PREFIX).unwrap().is_some());
-	}
-
 	#[test]
 	fn tree_route_works() {
 		let backend = Backend::<Block>::new_test(1000, 100);
 		let blockchain = backend.blockchain();
-		let block0 = insert_header(&backend, 0, Default::default(), Vec::new(), Default::default());
+		let block0 = insert_header(&backend, 0, Default::default(), None, Default::default());
 
 		// fork from genesis: 3 prong.
-		let a1 = insert_header(&backend, 1, block0, Vec::new(), Default::default());
-		let a2 = insert_header(&backend, 2, a1, Vec::new(), Default::default());
-		let a3 = insert_header(&backend, 3, a2, Vec::new(), Default::default());
+		let a1 = insert_header(&backend, 1, block0, None, Default::default());
+		let a2 = insert_header(&backend, 2, a1, None, Default::default());
+		let a3 = insert_header(&backend, 3, a2, None, Default::default());
 
 		// fork from genesis: 2 prong.
-		let b1 = insert_header(&backend, 1, block0, Vec::new(), H256::from([1; 32]));
-		let b2 = insert_header(&backend, 2, b1, Vec::new(), Default::default());
+		let b1 = insert_header(&backend, 1, block0, None, H256::from([1; 32]));
+		let b2 = insert_header(&backend, 2, b1, None, Default::default());
 
 		{
 			let tree_route = tree_route(blockchain, a3, b2).unwrap();
@@ -2397,8 +2062,8 @@ mod tests {
 		let backend = Backend::<Block>::new_test(1000, 100);
 		let blockchain = backend.blockchain();
 
-		let block0 = insert_header(&backend, 0, Default::default(), Vec::new(), Default::default());
-		let block1 = insert_header(&backend, 1, block0, Vec::new(), Default::default());
+		let block0 = insert_header(&backend, 0, Default::default(), None, Default::default());
+		let block1 = insert_header(&backend, 1, block0, None, Default::default());
 
 		{
 			let tree_route = tree_route(blockchain, block0, block1).unwrap();
@@ -2413,16 +2078,16 @@ mod tests {
 	fn lowest_common_ancestor_works() {
 		let backend = Backend::<Block>::new_test(1000, 100);
 		let blockchain = backend.blockchain();
-		let block0 = insert_header(&backend, 0, Default::default(), Vec::new(), Default::default());
+		let block0 = insert_header(&backend, 0, Default::default(), None, Default::default());
 
 		// fork from genesis: 3 prong.
-		let a1 = insert_header(&backend, 1, block0, Vec::new(), Default::default());
-		let a2 = insert_header(&backend, 2, a1, Vec::new(), Default::default());
-		let a3 = insert_header(&backend, 3, a2, Vec::new(), Default::default());
+		let a1 = insert_header(&backend, 1, block0, None, Default::default());
+		let a2 = insert_header(&backend, 2, a1, None, Default::default());
+		let a3 = insert_header(&backend, 3, a2, None, Default::default());
 
 		// fork from genesis: 2 prong.
-		let b1 = insert_header(&backend, 1, block0, Vec::new(), H256::from([1; 32]));
-		let b2 = insert_header(&backend, 2, b1, Vec::new(), Default::default());
+		let b1 = insert_header(&backend, 1, block0, None, H256::from([1; 32]));
+		let b2 = insert_header(&backend, 2, b1, None, Default::default());
 
 		{
 			let lca = lowest_common_ancestor(blockchain, a3, b2).unwrap();
@@ -2479,14 +2144,14 @@ mod tests {
 		let backend = Backend::<Block>::new_test(10000, 10000);
 		let blockchain = backend.blockchain();
 
-		let genesis = insert_header(&backend, 0, Default::default(), Vec::new(), Default::default());
+		let genesis = insert_header(&backend, 0, Default::default(), None, Default::default());
 
 		let block100 = (1..=100).fold(genesis, |parent, n| {
-			insert_header(&backend, n, parent, Vec::new(), Default::default())
+			insert_header(&backend, n, parent, None, Default::default())
 		});
 
 		let block7000 = (101..=7000).fold(block100, |parent, n| {
-			insert_header(&backend, n, parent, Vec::new(), Default::default())
+			insert_header(&backend, n, parent, None, Default::default())
 		});
 
 		// This will cause the ancestor of `block100` to be set to `genesis` as a side-effect.
@@ -2522,17 +2187,17 @@ mod tests {
 	#[test]
 	fn test_leaves_pruned_on_finality() {
 		let backend: Backend<Block> = Backend::new_test(10, 10);
-		let block0 = insert_header(&backend, 0, Default::default(), Default::default(), Default::default());
+		let block0 = insert_header(&backend, 0, Default::default(), None, Default::default());
 
-		let block1_a = insert_header(&backend, 1, block0, Default::default(), Default::default());
-		let block1_b = insert_header(&backend, 1, block0, Default::default(), [1; 32].into());
-		let block1_c = insert_header(&backend, 1, block0, Default::default(), [2; 32].into());
+		let block1_a = insert_header(&backend, 1, block0, None, Default::default());
+		let block1_b = insert_header(&backend, 1, block0, None, [1; 32].into());
+		let block1_c = insert_header(&backend, 1, block0, None, [2; 32].into());
 
 		assert_eq!(backend.blockchain().leaves().unwrap(), vec![block1_a, block1_b, block1_c]);
 
-		let block2_a = insert_header(&backend, 2, block1_a, Default::default(), Default::default());
-		let block2_b = insert_header(&backend, 2, block1_b, Default::default(), Default::default());
-		let block2_c = insert_header(&backend, 2, block1_b, Default::default(), [1; 32].into());
+		let block2_a = insert_header(&backend, 2, block1_a, None, Default::default());
+		let block2_b = insert_header(&backend, 2, block1_b, None, Default::default());
+		let block2_c = insert_header(&backend, 2, block1_b, None, [1; 32].into());
 
 		assert_eq!(backend.blockchain().leaves().unwrap(), vec![block2_a, block2_b, block2_c, block1_c]);
 
@@ -2559,8 +2224,8 @@ mod tests {
 
 		let backend = Backend::<Block>::new_test(10, 10);
 
-		let block0 = insert_header(&backend, 0, Default::default(), Default::default(), Default::default());
-		let _ = insert_header(&backend, 1, block0, Default::default(), Default::default());
+		let block0 = insert_header(&backend, 0, Default::default(), None, Default::default());
+		let _ = insert_header(&backend, 1, block0, None, Default::default());
 
 		let justification = Some(vec![1, 2, 3]);
 		backend.finalize_block(BlockId::Number(1), justification.clone()).unwrap();
@@ -2575,9 +2240,11 @@ mod tests {
 	fn test_finalize_multiple_blocks_in_single_op() {
 		let backend = Backend::<Block>::new_test(10, 10);
 
-		let block0 = insert_header(&backend, 0, Default::default(), Default::default(), Default::default());
-		let block1 = insert_header(&backend, 1, block0, Default::default(), Default::default());
-		let block2 = insert_header(&backend, 2, block1, Default::default(), Default::default());
+		let block0 = insert_header(&backend, 0, Default::default(), None, Default::default());
+		let block1 = insert_header(&backend, 1, block0, None, Default::default());
+		let block2 = insert_header(&backend, 2, block1, None, Default::default());
+		let block3 = insert_header(&backend, 3, block2, None, Default::default());
+		let block4 = insert_header(&backend, 4, block3, None, Default::default());
 		{
 			let mut op = backend.begin_operation().unwrap();
 			backend.begin_state_operation(&mut op, BlockId::Hash(block0)).unwrap();
@@ -2585,15 +2252,22 @@ mod tests {
 			op.mark_finalized(BlockId::Hash(block2), None).unwrap();
 			backend.commit_operation(op).unwrap();
 		}
+		{
+			let mut op = backend.begin_operation().unwrap();
+			backend.begin_state_operation(&mut op, BlockId::Hash(block2)).unwrap();
+			op.mark_finalized(BlockId::Hash(block3), None).unwrap();
+			op.mark_finalized(BlockId::Hash(block4), None).unwrap();
+			backend.commit_operation(op).unwrap();
+		}
 	}
 
 	#[test]
 	fn test_finalize_non_sequential() {
 		let backend = Backend::<Block>::new_test(10, 10);
 
-		let block0 = insert_header(&backend, 0, Default::default(), Default::default(), Default::default());
-		let block1 = insert_header(&backend, 1, block0, Default::default(), Default::default());
-		let block2 = insert_header(&backend, 2, block1, Default::default(), Default::default());
+		let block0 = insert_header(&backend, 0, Default::default(), None, Default::default());
+		let block1 = insert_header(&backend, 1, block0, None, Default::default());
+		let block2 = insert_header(&backend, 2, block1, None, Default::default());
 		{
 			let mut op = backend.begin_operation().unwrap();
 			backend.begin_state_operation(&mut op, BlockId::Hash(block0)).unwrap();
diff --git a/client/db/src/light.rs b/client/db/src/light.rs
index 8277f20b8d8ea..e663fc5699490 100644
--- a/client/db/src/light.rs
+++ b/client/db/src/light.rs
@@ -38,7 +38,7 @@ use codec::{Decode, Encode};
 use sp_runtime::generic::{DigestItem, BlockId};
 use sp_runtime::traits::{Block as BlockT, Header as HeaderT, Zero, One, NumberFor, HasherFor};
 use crate::cache::{DbCacheSync, DbCache, ComplexBlockId, EntryType as CacheEntryType};
-use crate::utils::{self, meta_keys, Meta, db_err, read_db, block_id_to_lookup_key, read_meta};
+use crate::utils::{self, meta_keys, DatabaseType, Meta, db_err, read_db, block_id_to_lookup_key, read_meta};
 use crate::{DatabaseSettings, FrozenForDuration};
 use log::{trace, warn, debug};
 
@@ -68,13 +68,10 @@ pub struct LightStorage<Block: BlockT> {
 	io_stats: FrozenForDuration<kvdb::IoStats>,
 }
 
-impl<Block> LightStorage<Block>
-	where
-		Block: BlockT,
-{
+impl<Block: BlockT> LightStorage<Block> {
 	/// Create new storage with given settings.
 	pub fn new(config: DatabaseSettings) -> ClientResult<Self> {
-		let db = crate::utils::open_database(&config, columns::META, "light")?;
+		let db = crate::utils::open_database::<Block>(&config, DatabaseType::Light)?;
 		Self::from_kvdb(db as Arc<_>)
 	}
 
@@ -89,7 +86,7 @@ impl<Block> LightStorage<Block>
 	}
 
 	fn from_kvdb(db: Arc<dyn KeyValueDB>) -> ClientResult<Self> {
-		let meta = read_meta::<Block>(&*db, columns::META, columns::HEADER)?;
+		let meta = read_meta::<Block>(&*db, columns::HEADER)?;
 		let cache = DbCache::new(
 			db.clone(),
 			columns::KEY_LOOKUP,
@@ -417,7 +414,7 @@ impl<Block> LightBlockchainStorage<Block> for LightStorage<Block>
 	fn import_header(
 		&self,
 		header: Block::Header,
-		cache_at: HashMap<well_known_cache_keys::Id, Vec<u8>>,
+		mut cache_at: HashMap<well_known_cache_keys::Id, Vec<u8>>,
 		leaf_state: NewBlockState,
 		aux_ops: Vec<(Vec<u8>, Option<Vec<u8>>)>,
 	) -> ClientResult<()> {
@@ -475,6 +472,13 @@ impl<Block> LightBlockchainStorage<Block> for LightStorage<Block>
 			)?;
 		}
 
+		// update changes trie configuration cache
+		if !cache_at.contains_key(&well_known_cache_keys::CHANGES_TRIE_CONFIG) {
+			if let Some(new_configuration) = crate::changes_tries_storage::extract_new_configuration(&header) {
+				cache_at.insert(well_known_cache_keys::CHANGES_TRIE_CONFIG, new_configuration.encode());
+			}
+		}
+
 		{
 			let mut cache = self.cache.0.write();
 			let cache_ops = cache.transaction(&mut transaction)
@@ -487,8 +491,11 @@ impl<Block> LightBlockchainStorage<Block> for LightStorage<Block>
 				.into_ops();
 
 			debug!("Light DB Commit {:?} ({})", hash, number);
+
 			self.db.write(transaction).map_err(db_err)?;
-			cache.commit(cache_ops);
+			cache.commit(cache_ops)
+				.expect("only fails if cache with given name isn't loaded yet;\
+						cache is already loaded because there are cache_ops; qed");
 		}
 
 		self.update_meta(hash, number, leaf_state.is_best(), finalized);
@@ -543,7 +550,9 @@ impl<Block> LightBlockchainStorage<Block> for LightStorage<Block>
 					.into_ops();
 
 				self.db.write(transaction).map_err(db_err)?;
-				cache.commit(cache_ops);
+				cache.commit(cache_ops)
+					.expect("only fails if cache with given name isn't loaded yet;\
+							cache is already loaded because there are cache_ops; qed");
 			}
 			self.update_meta(hash, header.number().clone(), false, true);
 
@@ -603,7 +612,8 @@ fn cht_key<N: TryInto<u32>>(cht_type: u8, block: N) -> ClientResult<[u8; 5]> {
 #[cfg(test)]
 pub(crate) mod tests {
 	use sc_client::cht;
-	use sp_runtime::generic::DigestItem;
+	use sp_core::ChangesTrieConfiguration;
+	use sp_runtime::generic::{DigestItem, ChangesTrieSignal};
 	use sp_runtime::testing::{H256 as Hash, Header, Block as RawBlock, ExtrinsicWrapper};
 	use sp_blockchain::{lowest_common_ancestor, tree_route};
 	use super::*;
@@ -964,7 +974,7 @@ pub(crate) mod tests {
 		}
 
 		fn get_authorities(cache: &dyn BlockchainCache<Block>, at: BlockId<Block>) -> Option<Vec<AuthorityId>> {
-			cache.get_at(&well_known_cache_keys::AUTHORITIES, &at)
+			cache.get_at(&well_known_cache_keys::AUTHORITIES, &at).unwrap_or(None)
 				.and_then(|(_, _, val)| Decode::decode(&mut &val[..]).ok())
 		}
 
@@ -1148,8 +1158,8 @@ pub(crate) mod tests {
 		let (genesis_hash, storage) = {
 			let db = LightStorage::<Block>::new_test();
 
-			// before cache is initialized => None
-			assert_eq!(db.cache().get_at(b"test", &BlockId::Number(0)), None);
+			// before cache is initialized => Err
+			assert!(db.cache().get_at(b"test", &BlockId::Number(0)).is_err());
 
 			// insert genesis block (no value for cache is provided)
 			let mut genesis_hash = None;
@@ -1160,14 +1170,14 @@ pub(crate) mod tests {
 			});
 
 			// after genesis is inserted => None
-			assert_eq!(db.cache().get_at(b"test", &BlockId::Number(0)), None);
+			assert_eq!(db.cache().get_at(b"test", &BlockId::Number(0)).unwrap(), None);
 
 			// initialize cache
 			db.cache().initialize(b"test", vec![42]).unwrap();
 
 			// after genesis is inserted + cache is initialized => Some
 			assert_eq!(
-				db.cache().get_at(b"test", &BlockId::Number(0)),
+				db.cache().get_at(b"test", &BlockId::Number(0)).unwrap(),
 				Some(((0, genesis_hash.unwrap()), None, vec![42])),
 			);
 
@@ -1177,8 +1187,37 @@ pub(crate) mod tests {
 		// restart && check that after restart value is read from the cache
 		let db = LightStorage::<Block>::from_kvdb(storage as Arc<_>).expect("failed to create test-db");
 		assert_eq!(
-			db.cache().get_at(b"test", &BlockId::Number(0)),
+			db.cache().get_at(b"test", &BlockId::Number(0)).unwrap(),
 			Some(((0, genesis_hash.unwrap()), None, vec![42])),
 		);
 	}
+
+	#[test]
+	fn changes_trie_configuration_is_tracked_on_light_client() {
+		let db = LightStorage::<Block>::new_test();
+
+		let new_config = Some(ChangesTrieConfiguration::new(2, 2));
+
+		// insert block#0 && block#1 (no value for cache is provided)
+		let hash0 = insert_block(&db, HashMap::new(), || default_header(&Default::default(), 0));
+		assert_eq!(
+			db.cache().get_at(&well_known_cache_keys::CHANGES_TRIE_CONFIG, &BlockId::Number(0)).unwrap()
+				.map(|(_, _, v)| ChangesTrieConfiguration::decode(&mut &v[..]).unwrap()),
+			None,
+		);
+
+		// insert configuration at block#1 (starts from block#2)
+		insert_block(&db, HashMap::new(), || {
+			let mut header = default_header(&hash0, 1);
+			header.digest_mut().push(
+				DigestItem::ChangesTrieSignal(ChangesTrieSignal::NewConfiguration(new_config.clone()))
+			);
+			header
+		});
+		assert_eq!(
+			db.cache().get_at(&well_known_cache_keys::CHANGES_TRIE_CONFIG, &BlockId::Number(1)).unwrap()
+				.map(|(_, _, v)| Option::<ChangesTrieConfiguration>::decode(&mut &v[..]).unwrap()),
+			Some(new_config),
+		);
+	}
 }
diff --git a/client/db/src/storage_cache.rs b/client/db/src/storage_cache.rs
index 4f7e906a0ae28..fd85a899b628e 100644
--- a/client/db/src/storage_cache.rs
+++ b/client/db/src/storage_cache.rs
@@ -24,17 +24,17 @@ use hash_db::Hasher;
 use sp_runtime::traits::{Block as BlockT, Header, HasherFor, NumberFor};
 use sp_core::hexdisplay::HexDisplay;
 use sp_core::storage::ChildInfo;
-use sp_state_machine::{backend::Backend as StateBackend, TrieBackend};
+use sp_state_machine::{
+	backend::Backend as StateBackend, TrieBackend, StorageKey, StorageValue,
+	StorageCollection, ChildStorageCollection,
+};
 use log::trace;
-use sc_client_api::backend::{StorageCollection, ChildStorageCollection};
 use std::hash::Hash as StdHash;
 use crate::stats::StateUsageStats;
 
 const STATE_CACHE_BLOCKS: usize = 12;
 
-type StorageKey = Vec<u8>;
 type ChildStorageKey = (Vec<u8>, Vec<u8>);
-type StorageValue = Vec<u8>;
 
 /// Shared canonical state cache.
 pub struct Cache<B: BlockT> {
diff --git a/client/db/src/upgrade.rs b/client/db/src/upgrade.rs
new file mode 100644
index 0000000000000..ab2d4bbf799b2
--- /dev/null
+++ b/client/db/src/upgrade.rs
@@ -0,0 +1,198 @@
+// Copyright 2019-2020 Parity Technologies (UK) Ltd.
+// This file is part of Substrate.
+
+// Substrate is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Substrate is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Substrate.  If not, see <http://www.gnu.org/licenses/>.
+
+//! Database upgrade logic.
+
+use std::fs;
+use std::io::{Read, Write, ErrorKind};
+use std::path::{Path, PathBuf};
+use std::sync::Arc;
+
+use codec::Encode;
+use kvdb_rocksdb::{Database, DatabaseConfig};
+use parking_lot::RwLock;
+use sp_blockchain::{well_known_cache_keys, Cache};
+use sp_core::ChangesTrieConfiguration;
+use sp_runtime::traits::Block as BlockT;
+use crate::{
+	cache::{ComplexBlockId, DbCache, DbCacheSync},
+	utils::{DatabaseType, check_database_type, db_err, read_genesis_hash},
+};
+
+/// Version file name.
+const VERSION_FILE_NAME: &'static str = "db_version";
+
+/// Current db version.
+const CURRENT_VERSION: u32 = 1;
+
+/// Number of columns in v0.
+const V0_NUM_COLUMNS: u32 = 10;
+
+/// Upgrade database to current version.
+pub fn upgrade_db<Block: BlockT>(db_path: &Path, db_type: DatabaseType) -> sp_blockchain::Result<()> {
+	let db_version = current_version(db_path)?;
+	match db_version {
+		0 => migrate_0_to_1::<Block>(db_path, db_type)?,
+		1 => (),
+		_ => Err(sp_blockchain::Error::Backend(format!("Future database version: {}", db_version)))?,
+	}
+
+	update_version(db_path)
+}
+
+/// Migration from version0 to version1:
+/// 1) the number of columns has changed from 10 to 11;
+/// 2) changes tries configuration are now cached.
+fn migrate_0_to_1<Block: BlockT>(db_path: &Path, db_type: DatabaseType) -> sp_blockchain::Result<()> {
+	{
+		let db = open_database(db_path, db_type, V0_NUM_COLUMNS)?;
+		db.add_column().map_err(db_err)?;
+		db.flush().map_err(db_err)?;
+	}
+
+	let db = open_database(db_path, db_type, V0_NUM_COLUMNS + 1)?;
+
+	const V0_FULL_KEY_LOOKUP_COLUMN: u32 = 3;
+	const V0_FULL_HEADER_COLUMN: u32 = 4;
+	const V0_FULL_CACHE_COLUMN: u32 = 10; // that's the column we have just added
+	const V0_LIGHT_KEY_LOOKUP_COLUMN: u32 = 1;
+	const V0_LIGHT_HEADER_COLUMN: u32 = 2;
+	const V0_LIGHT_CACHE_COLUMN: u32 = 3;
+
+	let (key_lookup_column, header_column, cache_column) = match db_type {
+		DatabaseType::Full => (
+			V0_FULL_KEY_LOOKUP_COLUMN,
+			V0_FULL_HEADER_COLUMN,
+			V0_FULL_CACHE_COLUMN,
+		),
+		DatabaseType::Light => (
+			V0_LIGHT_KEY_LOOKUP_COLUMN,
+			V0_LIGHT_HEADER_COLUMN,
+			V0_LIGHT_CACHE_COLUMN,
+		),
+	};
+
+	let genesis_hash: Option<Block::Hash> = read_genesis_hash(&db)?;
+	if let Some(genesis_hash) = genesis_hash {
+		let cache: DbCacheSync<Block> = DbCacheSync(RwLock::new(DbCache::new(
+			Arc::new(db),
+			key_lookup_column,
+			header_column,
+			cache_column,
+			genesis_hash,
+			ComplexBlockId::new(genesis_hash, 0.into()),
+		)));
+		let changes_trie_config: Option<ChangesTrieConfiguration> = None;
+		cache.initialize(&well_known_cache_keys::CHANGES_TRIE_CONFIG, changes_trie_config.encode())?;
+	}
+
+	Ok(())
+}
+
+/// Reads current database version from the file at given path.
+/// If the file does not exist returns 0.
+fn current_version(path: &Path) -> sp_blockchain::Result<u32> {
+	let unknown_version_err = || sp_blockchain::Error::Backend("Unknown database version".into());
+
+	match fs::File::open(version_file_path(path)) {
+		Err(ref err) if err.kind() == ErrorKind::NotFound => Ok(0),
+		Err(_) => Err(unknown_version_err()),
+		Ok(mut file) => {
+			let mut s = String::new();
+			file.read_to_string(&mut s).map_err(|_| unknown_version_err())?;
+			u32::from_str_radix(&s, 10).map_err(|_| unknown_version_err())
+		},
+	}
+}
+
+/// Opens database of givent type with given number of columns.
+fn open_database(db_path: &Path, db_type: DatabaseType, db_columns: u32) -> sp_blockchain::Result<Database> {
+	let db_path = db_path.to_str()
+		.ok_or_else(|| sp_blockchain::Error::Backend("Invalid database path".into()))?;
+	let db_cfg = DatabaseConfig::with_columns(db_columns);
+	let db = Database::open(&db_cfg, db_path).map_err(db_err)?;
+	check_database_type(&db, db_type)?;
+	Ok(db)
+}
+
+/// Writes current database version to the file.
+/// Creates a new file if the version file does not exist yet.
+fn update_version(path: &Path) -> sp_blockchain::Result<()> {
+	fs::create_dir_all(path).map_err(db_err)?;
+	let mut file = fs::File::create(version_file_path(path)).map_err(db_err)?;
+	file.write_all(format!("{}", CURRENT_VERSION).as_bytes()).map_err(db_err)?;
+	Ok(())
+}
+
+/// Returns the version file path.
+fn version_file_path(path: &Path) -> PathBuf {
+	let mut file_path = path.to_owned();
+	file_path.push(VERSION_FILE_NAME);
+	file_path
+}
+
+#[cfg(test)]
+mod tests {
+	use sc_state_db::PruningMode;
+	use crate::{DatabaseSettings, DatabaseSettingsSrc};
+	use crate::tests::Block;
+	use super::*;
+
+	fn create_db(db_path: &Path, version: Option<u32>) {
+		let db_cfg = DatabaseConfig::with_columns(V0_NUM_COLUMNS);
+		Database::open(&db_cfg, db_path.to_str().unwrap()).unwrap();
+		if let Some(version) = version {
+			fs::create_dir_all(db_path).unwrap();
+			let mut file = fs::File::create(version_file_path(db_path)).unwrap();
+			file.write_all(format!("{}", version).as_bytes()).unwrap();
+		}
+	}
+
+	fn open_database(db_path: &Path) -> sp_blockchain::Result<()> {
+		crate::utils::open_database::<Block>(&DatabaseSettings {
+			state_cache_size: 0,
+			state_cache_child_ratio: None,
+			pruning: PruningMode::ArchiveAll,
+			source: DatabaseSettingsSrc::Path { path: db_path.to_owned(), cache_size: None },
+		}, DatabaseType::Full).map(|_| ())
+	}
+
+	#[test]
+	fn downgrade_never_happens() {
+		let db_dir = tempdir::TempDir::new("").unwrap();
+		create_db(db_dir.path(), Some(CURRENT_VERSION + 1));
+		assert!(open_database(db_dir.path()).is_err());
+	}
+
+	#[test]
+	fn open_empty_database_works() {
+		let db_dir = tempdir::TempDir::new("").unwrap();
+		open_database(db_dir.path()).unwrap();
+		open_database(db_dir.path()).unwrap();
+		assert_eq!(current_version(db_dir.path()).unwrap(), CURRENT_VERSION);
+	}
+
+	#[test]
+	fn upgrade_from_0_to_1_works() {
+		for version_from_file in &[None, Some(0)] {
+			let db_dir = tempdir::TempDir::new("").unwrap();
+			let db_path = db_dir.path();
+			create_db(db_path, *version_from_file);
+			open_database(db_path).unwrap();
+			assert_eq!(current_version(db_path).unwrap(), CURRENT_VERSION);
+		}
+	}
+}
diff --git a/client/db/src/utils.rs b/client/db/src/utils.rs
index ed7b2220aacd5..f7f51d7f6de5d 100644
--- a/client/db/src/utils.rs
+++ b/client/db/src/utils.rs
@@ -21,7 +21,7 @@ use std::sync::Arc;
 use std::{io, convert::TryInto};
 
 use kvdb::{KeyValueDB, DBTransaction};
-#[cfg(feature = "kvdb-rocksdb")]
+#[cfg(any(feature = "kvdb-rocksdb", test))]
 use kvdb_rocksdb::{Database, DatabaseConfig};
 use log::debug;
 
@@ -36,7 +36,7 @@ use crate::{DatabaseSettings, DatabaseSettingsSrc};
 
 /// Number of columns in the db. Must be the same for both full && light dbs.
 /// Otherwise RocksDb will fail to open database && check its type.
-pub const NUM_COLUMNS: u32 = 10;
+pub const NUM_COLUMNS: u32 = 11;
 /// Meta column. The set of keys in the column is shared by full && light storages.
 pub const COLUMN_META: u32 = 0;
 
@@ -50,6 +50,8 @@ pub mod meta_keys {
 	pub const FINALIZED_BLOCK: &[u8; 5] = b"final";
 	/// Meta information prefix for list-based caches.
 	pub const CACHE_META_PREFIX: &[u8; 5] = b"cache";
+	/// Meta information for changes tries key.
+	pub const CHANGES_TRIES_META: &[u8; 5] = b"ctrie";
 	/// Genesis block hash.
 	pub const GENESIS_HASH: &[u8; 3] = b"gen";
 	/// Leaves prefix list key.
@@ -76,6 +78,15 @@ pub struct Meta<N, H> {
 /// A block lookup key: used for canonical lookup from block number to hash
 pub type NumberIndexKey = [u8; 4];
 
+/// Database type.
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub enum DatabaseType {
+	/// Full node database.
+	Full,
+	/// Light node database.
+	Light,
+}
+
 /// Convert block number into short lookup key (LE representation) for
 /// blocks that are in the canonical chain.
 ///
@@ -203,14 +214,17 @@ pub fn db_err(err: io::Error) -> sp_blockchain::Error {
 }
 
 /// Open RocksDB database.
-pub fn open_database(
+pub fn open_database<Block: BlockT>(
 	config: &DatabaseSettings,
-	col_meta: u32,
-	db_type: &str
+	db_type: DatabaseType,
 ) -> sp_blockchain::Result<Arc<dyn KeyValueDB>> {
 	let db: Arc<dyn KeyValueDB> = match &config.source {
-		#[cfg(feature = "kvdb-rocksdb")]
+		#[cfg(any(feature = "kvdb-rocksdb", test))]
 		DatabaseSettingsSrc::Path { path, cache_size } => {
+			// first upgrade database to required version
+			crate::upgrade::upgrade_db::<Block>(&path, db_type)?;
+
+			// and now open database assuming that it has the latest version
 			let mut db_config = DatabaseConfig::with_columns(NUM_COLUMNS);
 
 			if let Some(cache_size) = cache_size {
@@ -232,7 +246,7 @@ pub fn open_database(
 				.ok_or_else(|| sp_blockchain::Error::Backend("Invalid database path".into()))?;
 			Arc::new(Database::open(&db_config, &path).map_err(db_err)?)
 		},
-		#[cfg(not(feature = "kvdb-rocksdb"))]
+		#[cfg(not(any(feature = "kvdb-rocksdb", test)))]
 		DatabaseSettingsSrc::Path { .. } => {
 			let msg = "Try to open RocksDB database with RocksDB disabled".into();
 			return Err(sp_blockchain::Error::Backend(msg));
@@ -240,22 +254,28 @@ pub fn open_database(
 		DatabaseSettingsSrc::Custom(db) => db.clone(),
 	};
 
-	// check database type
-	match db.get(col_meta, meta_keys::TYPE).map_err(db_err)? {
+	check_database_type(&*db, db_type)?;
+
+	Ok(db)
+}
+
+/// Check database type.
+pub fn check_database_type(db: &dyn KeyValueDB, db_type: DatabaseType) -> sp_blockchain::Result<()> {
+	match db.get(COLUMN_META, meta_keys::TYPE).map_err(db_err)? {
 		Some(stored_type) => {
-			if db_type.as_bytes() != &*stored_type {
+			if db_type.as_str().as_bytes() != &*stored_type {
 				return Err(sp_blockchain::Error::Backend(
-					format!("Unexpected database type. Expected: {}", db_type)).into());
+					format!("Unexpected database type. Expected: {}", db_type.as_str())).into());
 			}
 		},
 		None => {
 			let mut transaction = DBTransaction::new();
-			transaction.put(col_meta, meta_keys::TYPE, db_type.as_bytes());
+			transaction.put(COLUMN_META, meta_keys::TYPE, db_type.as_str().as_bytes());
 			db.write(transaction).map_err(db_err)?;
 		},
 	}
 
-	Ok(db)
+	Ok(())
 }
 
 /// Read database column entry for the given block.
@@ -304,20 +324,15 @@ pub fn require_header<Block: BlockT>(
 }
 
 /// Read meta from the database.
-pub fn read_meta<Block>(db: &dyn KeyValueDB, col_meta: u32, col_header: u32) -> Result<
+pub fn read_meta<Block>(db: &dyn KeyValueDB, col_header: u32) -> Result<
 	Meta<<<Block as BlockT>::Header as HeaderT>::Number, Block::Hash>,
 	sp_blockchain::Error,
 >
 	where
 		Block: BlockT,
 {
-	let genesis_hash: Block::Hash = match db.get(col_meta, meta_keys::GENESIS_HASH).map_err(db_err)? {
-		Some(h) => match Decode::decode(&mut &h[..]) {
-			Ok(h) => h,
-			Err(err) => return Err(sp_blockchain::Error::Backend(
-				format!("Error decoding genesis hash: {}", err)
-			)),
-		},
+	let genesis_hash: Block::Hash = match read_genesis_hash(db)? {
+		Some(genesis_hash) => genesis_hash,
 		None => return Ok(Meta {
 			best_hash: Default::default(),
 			best_number: Zero::zero(),
@@ -328,7 +343,7 @@ pub fn read_meta<Block>(db: &dyn KeyValueDB, col_meta: u32, col_header: u32) ->
 	};
 
 	let load_meta_block = |desc, key| -> Result<_, sp_blockchain::Error> {
-		if let Some(Some(header)) = db.get(col_meta, key).and_then(|id|
+		if let Some(Some(header)) = db.get(COLUMN_META, key).and_then(|id|
 			match id {
 				Some(id) => db.get(col_header, &id).map(|h| h.map(|b| Block::Header::decode(&mut &b[..]).ok())),
 				None => Ok(None),
@@ -354,6 +369,29 @@ pub fn read_meta<Block>(db: &dyn KeyValueDB, col_meta: u32, col_header: u32) ->
 	})
 }
 
+/// Read genesis hash from database.
+pub fn read_genesis_hash<Hash: Decode>(db: &dyn KeyValueDB) -> sp_blockchain::Result<Option<Hash>> {
+	match db.get(COLUMN_META, meta_keys::GENESIS_HASH).map_err(db_err)? {
+		Some(h) => match Decode::decode(&mut &h[..]) {
+			Ok(h) => Ok(Some(h)),
+			Err(err) => Err(sp_blockchain::Error::Backend(
+				format!("Error decoding genesis hash: {}", err)
+			)),
+		},
+		None => Ok(None),
+	}
+}
+
+impl DatabaseType {
+	/// Returns str representation of the type.
+	pub fn as_str(&self) -> &'static str {
+		match *self {
+			DatabaseType::Full => "full",
+			DatabaseType::Light => "light",
+		}
+	}
+}
+
 #[cfg(test)]
 mod tests {
 	use super::*;
@@ -368,4 +406,10 @@ mod tests {
 			_ => unreachable!(),
 		};
 	}
+
+	#[test]
+	fn database_type_as_str_works() {
+		assert_eq!(DatabaseType::Full.as_str(), "full");
+		assert_eq!(DatabaseType::Light.as_str(), "light");
+	}
 }
diff --git a/client/executor/Cargo.toml b/client/executor/Cargo.toml
index a2f6ebaac0e3c..aa8c46999d98d 100644
--- a/client/executor/Cargo.toml
+++ b/client/executor/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "sc-executor"
-version = "2.0.0"
+version = "0.8.0"
 authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2018"
 
@@ -18,10 +18,10 @@ parity-wasm = "0.41.0"
 lazy_static = "1.4.0"
 sp-wasm-interface = { version = "2.0.0", path = "../../primitives/wasm-interface" }
 sp-runtime-interface = { version = "2.0.0", path = "../../primitives/runtime-interface" }
-sp-externalities = { version = "2.0.0", path = "../../primitives/externalities" }
-sc-executor-common = { version = "2.0.0", path = "common" }
-sc-executor-wasmi = { version = "2.0.0", path = "wasmi" }
-sc-executor-wasmtime = { version = "2.0.0", path = "wasmtime", optional = true }
+sp-externalities = { version = "0.8.0", path = "../../primitives/externalities" }
+sc-executor-common = { version = "0.8", path = "common" }
+sc-executor-wasmi = { version = "0.8", path = "wasmi" }
+sc-executor-wasmtime = { version = "0.8", path = "wasmtime", optional = true }
 parking_lot = "0.9.0"
 log = "0.4.8"
 libsecp256k1 = "0.3.4"
@@ -32,7 +32,7 @@ wabt = "0.9.2"
 hex-literal = "0.2.1"
 sc-runtime-test = { version = "2.0.0", path = "runtime-test" }
 substrate-test-runtime = { version = "2.0.0", path = "../../test-utils/runtime" }
-sp-state-machine = { version = "2.0.0", path = "../../primitives/state-machine" }
+sp-state-machine = { version = "0.8", path = "../../primitives/state-machine" }
 test-case = "0.3.3"
 
 [features]
diff --git a/client/executor/common/Cargo.toml b/client/executor/common/Cargo.toml
index ddd40de62bbb1..cae0876217993 100644
--- a/client/executor/common/Cargo.toml
+++ b/client/executor/common/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "sc-executor-common"
-version = "2.0.0"
+version = "0.8.0"
 authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2018"
 
diff --git a/client/executor/common/src/error.rs b/client/executor/common/src/error.rs
index fca17bd88c8ea..f7de0af9685d7 100644
--- a/client/executor/common/src/error.rs
+++ b/client/executor/common/src/error.rs
@@ -57,6 +57,10 @@ pub enum Error {
 	/// Runtime failed.
 	#[display(fmt="Runtime error")]
 	Runtime,
+	/// Runtime panicked.
+	#[display(fmt="Runtime panicked: {}", _0)]
+	#[from(ignore)]
+	RuntimePanicked(String),
 	/// Invalid memory reference.
 	#[display(fmt="Invalid memory reference")]
 	InvalidMemoryReference,
diff --git a/client/executor/common/src/wasm_runtime.rs b/client/executor/common/src/wasm_runtime.rs
index 78c05c4c29b68..0733350f4cd6a 100644
--- a/client/executor/common/src/wasm_runtime.rs
+++ b/client/executor/common/src/wasm_runtime.rs
@@ -17,7 +17,6 @@
 //! Definitions for a wasm runtime.
 
 use crate::error::Error;
-use sp_core::traits::Externalities;
 use sp_wasm_interface::Function;
 
 /// A trait that defines an abstract wasm runtime.
@@ -34,6 +33,5 @@ pub trait WasmRuntime {
 	fn host_functions(&self) -> &[&'static dyn Function];
 
 	/// Call a method in the Substrate runtime by name. Returns the encoded result on success.
-	fn call(&mut self, ext: &mut dyn Externalities, method: &str, data: &[u8])
-		-> Result<Vec<u8>, Error>;
+	fn call(&mut self, method: &str, data: &[u8]) -> Result<Vec<u8>, Error>;
 }
diff --git a/client/executor/runtime-test/Cargo.toml b/client/executor/runtime-test/Cargo.toml
index ba88550a92ef7..835021fec2a11 100644
--- a/client/executor/runtime-test/Cargo.toml
+++ b/client/executor/runtime-test/Cargo.toml
@@ -8,7 +8,7 @@ build = "build.rs"
 [dependencies]
 sp-std = { version = "2.0.0", default-features = false, path = "../../../primitives/std" }
 sp-io = { version = "2.0.0", default-features = false, path = "../../../primitives/io" }
-sp-sandbox = { version = "2.0.0", default-features = false, path = "../../../primitives/sandbox" }
+sp-sandbox = { version = "0.8.0", default-features = false, path = "../../../primitives/sandbox" }
 sp-core = { version = "2.0.0", default-features = false, path = "../../../primitives/core" }
 sp-runtime = { version = "2.0.0", default-features = false, path = "../../../primitives/runtime" }
 
diff --git a/client/executor/src/integration_tests/mod.rs b/client/executor/src/integration_tests/mod.rs
index 2d39cac414545..00f4eb33b02bf 100644
--- a/client/executor/src/integration_tests/mod.rs
+++ b/client/executor/src/integration_tests/mod.rs
@@ -83,7 +83,7 @@ fn call_in_wasm<E: Externalities>(
 	code: &[u8],
 	heap_pages: u64,
 ) -> crate::error::Result<Vec<u8>> {
-	crate::call_in_wasm::<E, HostFunctions>(
+	crate::call_in_wasm::<HostFunctions>(
 		function,
 		call_data,
 		execution_method,
diff --git a/client/executor/src/lib.rs b/client/executor/src/lib.rs
index 1908eb3688ea3..4f97efa9b661e 100644
--- a/client/executor/src/lib.rs
+++ b/client/executor/src/lib.rs
@@ -39,7 +39,7 @@ mod wasm_runtime;
 mod integration_tests;
 
 pub use wasmi;
-pub use native_executor::{with_native_environment, NativeExecutor, NativeExecutionDispatch};
+pub use native_executor::{with_externalities_safe, NativeExecutor, NativeExecutionDispatch};
 pub use sp_version::{RuntimeVersion, NativeVersion};
 pub use codec::Codec;
 #[doc(hidden)]
@@ -57,26 +57,55 @@ pub use sc_executor_common::{error, allocator, sandbox};
 /// - `call_data`: Will be given as input parameters to `function`
 /// - `execution_method`: The execution method to use.
 /// - `ext`: The externalities that should be set while executing the wasm function.
+///          If `None` is given, no externalities will be set.
 /// - `heap_pages`: The number of heap pages to allocate.
 ///
 /// Returns the `Vec<u8>` that contains the return value of the function.
-pub fn call_in_wasm<E: Externalities, HF: sp_wasm_interface::HostFunctions>(
+pub fn call_in_wasm<HF: sp_wasm_interface::HostFunctions>(
 	function: &str,
 	call_data: &[u8],
 	execution_method: WasmExecutionMethod,
-	ext: &mut E,
+	ext: &mut dyn Externalities,
 	code: &[u8],
 	heap_pages: u64,
 	allow_missing_imports: bool,
 ) -> error::Result<Vec<u8>> {
-	let mut instance = wasm_runtime::create_wasm_runtime_with_code(
+	call_in_wasm_with_host_functions(
+		function,
+		call_data,
 		execution_method,
-		heap_pages,
+		ext,
 		code,
+		heap_pages,
 		HF::host_functions(),
 		allow_missing_imports,
+	)
+}
+
+/// Non-generic version of [`call_in_wasm`] that takes the `host_functions` as parameter.
+/// For more information please see [`call_in_wasm`].
+pub fn call_in_wasm_with_host_functions(
+	function: &str,
+	call_data: &[u8],
+	execution_method: WasmExecutionMethod,
+	ext: &mut dyn Externalities,
+	code: &[u8],
+	heap_pages: u64,
+	host_functions: Vec<&'static dyn sp_wasm_interface::Function>,
+	allow_missing_imports: bool,
+) -> error::Result<Vec<u8>> {
+	let instance = wasm_runtime::create_wasm_runtime_with_code(
+		execution_method,
+		heap_pages,
+		code,
+		host_functions,
+		allow_missing_imports,
 	)?;
-	instance.call(ext, function, call_data)
+
+	// It is safe, as we delete the instance afterwards.
+	let mut instance = std::panic::AssertUnwindSafe(instance);
+
+	with_externalities_safe(ext, move || instance.call(function, call_data)).and_then(|r| r)
 }
 
 /// Provides runtime information.
@@ -98,7 +127,7 @@ mod tests {
 	fn call_in_interpreted_wasm_works() {
 		let mut ext = TestExternalities::default();
 		let mut ext = ext.ext();
-		let res = call_in_wasm::<_, sp_io::SubstrateHostFunctions>(
+		let res = call_in_wasm::<sp_io::SubstrateHostFunctions>(
 			"test_empty_return",
 			&[],
 			WasmExecutionMethod::Interpreted,
diff --git a/client/executor/src/native_executor.rs b/client/executor/src/native_executor.rs
index 86b274eea0bb9..4fe7a205f53f9 100644
--- a/client/executor/src/native_executor.rs
+++ b/client/executor/src/native_executor.rs
@@ -22,7 +22,7 @@ use sp_version::{NativeVersion, RuntimeVersion};
 use codec::{Decode, Encode};
 use sp_core::{NativeOrEncoded, traits::{CodeExecutor, Externalities}};
 use log::trace;
-use std::{result, cell::RefCell, panic::{UnwindSafe, AssertUnwindSafe}};
+use std::{result, cell::RefCell, panic::{UnwindSafe, AssertUnwindSafe}, sync::Arc};
 use sp_wasm_interface::{HostFunctions, Function};
 use sc_executor_common::wasm_runtime::WasmRuntime;
 
@@ -33,22 +33,29 @@ thread_local! {
 /// Default num of pages for the heap
 const DEFAULT_HEAP_PAGES: u64 = 1024;
 
-pub(crate) fn safe_call<F, U>(f: F) -> Result<U>
-	where F: UnwindSafe + FnOnce() -> U
-{
-	// Substrate uses custom panic hook that terminates process on panic. Disable
-	// termination for the native call.
-	let _guard = sp_panic_handler::AbortGuard::force_unwind();
-	std::panic::catch_unwind(f).map_err(|_| Error::Runtime)
-}
-
-/// Set up the externalities and safe calling environment to execute calls to a native runtime.
+/// Set up the externalities and safe calling environment to execute runtime calls.
 ///
 /// If the inner closure panics, it will be caught and return an error.
-pub fn with_native_environment<F, U>(ext: &mut dyn Externalities, f: F) -> Result<U>
+pub fn with_externalities_safe<F, U>(ext: &mut dyn Externalities, f: F) -> Result<U>
 	where F: UnwindSafe + FnOnce() -> U
 {
-	sp_externalities::set_and_run_with_externalities(ext, move || safe_call(f))
+	sp_externalities::set_and_run_with_externalities(
+		ext,
+		move || {
+			// Substrate uses custom panic hook that terminates process on panic. Disable
+			// termination for the native call.
+			let _guard = sp_panic_handler::AbortGuard::force_unwind();
+			std::panic::catch_unwind(f).map_err(|e| {
+				if let Some(err) = e.downcast_ref::<String>() {
+					Error::RuntimePanicked(err.clone())
+				} else if let Some(err) = e.downcast_ref::<&'static str>() {
+					Error::RuntimePanicked(err.to_string())
+				} else {
+					Error::RuntimePanicked("Unknown panic".into())
+				}
+			})
+		},
+	)
 }
 
 /// Delegate for dispatching a CodeExecutor call.
@@ -80,7 +87,7 @@ pub struct NativeExecutor<D> {
 	/// The number of 64KB pages to allocate for Wasm execution.
 	default_heap_pages: u64,
 	/// The host functions registered with this instance.
-	host_functions: Vec<&'static dyn Function>,
+	host_functions: Arc<Vec<&'static dyn Function>>,
 }
 
 impl<D: NativeExecutionDispatch> NativeExecutor<D> {
@@ -107,7 +114,7 @@ impl<D: NativeExecutionDispatch> NativeExecutor<D> {
 			fallback_method,
 			native_version: D::native_version(),
 			default_heap_pages: default_heap_pages.unwrap_or(DEFAULT_HEAP_PAGES),
-			host_functions,
+			host_functions: Arc::new(host_functions),
 		}
 	}
 
@@ -139,7 +146,7 @@ impl<D: NativeExecutionDispatch> NativeExecutor<D> {
 				ext,
 				self.fallback_method,
 				self.default_heap_pages,
-				&self.host_functions,
+				&*self.host_functions,
 			)?;
 
 			let runtime = AssertUnwindSafe(runtime);
@@ -181,7 +188,7 @@ impl<D: NativeExecutionDispatch> RuntimeInfo for NativeExecutor<D> {
 	}
 }
 
-impl<D: NativeExecutionDispatch> CodeExecutor for NativeExecutor<D> {
+impl<D: NativeExecutionDispatch + 'static> CodeExecutor for NativeExecutor<D> {
 	type Error = Error;
 
 	fn call
@@ -212,13 +219,15 @@ impl<D: NativeExecutionDispatch> CodeExecutor for NativeExecutor<D> {
 						onchain_version,
 					);
 
-					safe_call(
-						move || runtime.call(&mut **ext, method, data).map(NativeOrEncoded::Encoded)
+					with_externalities_safe(
+						&mut **ext,
+						move || runtime.call(method, data).map(NativeOrEncoded::Encoded)
 					)
 				}
 				(false, _, _) => {
-					safe_call(
-						move || runtime.call(&mut **ext, method, data).map(NativeOrEncoded::Encoded)
+					with_externalities_safe(
+						&mut **ext,
+						move || runtime.call(method, data).map(NativeOrEncoded::Encoded)
 					)
 				},
 				(true, true, Some(call)) => {
@@ -230,7 +239,7 @@ impl<D: NativeExecutionDispatch> CodeExecutor for NativeExecutor<D> {
 					);
 
 					used_native = true;
-					let res = with_native_environment(&mut **ext, move || (call)())
+					let res = with_externalities_safe(&mut **ext, move || (call)())
 						.and_then(|r| r
 							.map(NativeOrEncoded::Native)
 							.map_err(|s| Error::ApiError(s.to_string()))
@@ -255,6 +264,27 @@ impl<D: NativeExecutionDispatch> CodeExecutor for NativeExecutor<D> {
 	}
 }
 
+impl<D: NativeExecutionDispatch> sp_core::traits::CallInWasm for NativeExecutor<D> {
+	fn call_in_wasm(
+		&self,
+		wasm_blob: &[u8],
+		method: &str,
+		call_data: &[u8],
+		ext: &mut dyn Externalities,
+	) -> std::result::Result<Vec<u8>, String> {
+		crate::call_in_wasm_with_host_functions(
+			method,
+			call_data,
+			self.fallback_method,
+			ext,
+			wasm_blob,
+			self.default_heap_pages,
+			(*self.host_functions).clone(),
+			false,
+		).map_err(|e| e.to_string())
+	}
+}
+
 /// Implements a `NativeExecutionDispatch` for provided parameters.
 ///
 /// # Example
@@ -318,7 +348,7 @@ macro_rules! native_executor_instance {
 				method: &str,
 				data: &[u8]
 			) -> $crate::error::Result<Vec<u8>> {
-				$crate::with_native_environment(ext, move || $dispatcher(method, data))?
+				$crate::with_externalities_safe(ext, move || $dispatcher(method, data))?
 					.ok_or_else(|| $crate::error::Error::MethodNotFound(method.to_owned()))
 			}
 
diff --git a/client/executor/src/wasm_runtime.rs b/client/executor/src/wasm_runtime.rs
index eef73097f6e7b..036b28f764003 100644
--- a/client/executor/src/wasm_runtime.rs
+++ b/client/executor/src/wasm_runtime.rs
@@ -223,8 +223,9 @@ fn create_versioned_wasm_runtime<E: Externalities>(
 		// The following unwind safety assertion is OK because if the method call panics, the
 		// runtime will be dropped.
 		let mut runtime = AssertUnwindSafe(runtime.as_mut());
-		crate::native_executor::safe_call(
-			move || runtime.call(&mut **ext, "Core_version", &[])
+		crate::native_executor::with_externalities_safe(
+			&mut **ext,
+			move || runtime.call("Core_version", &[])
 		).map_err(|_| WasmError::Instantiation("panic in call to get runtime version".into()))?
 	};
 	let encoded_version = version_result
diff --git a/client/executor/wasmi/Cargo.toml b/client/executor/wasmi/Cargo.toml
index 7a13d7ea97e26..dbfdc505c647a 100644
--- a/client/executor/wasmi/Cargo.toml
+++ b/client/executor/wasmi/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "sc-executor-wasmi"
-version = "2.0.0"
+version = "0.8.0"
 authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2018"
 
@@ -9,8 +9,7 @@ log = "0.4.8"
 wasmi = "0.6.2"
 parity-wasm = "0.41.0"
 codec = { package = "parity-scale-codec", version = "1.0.0" }
-sc-executor-common = { version = "2.0.0", path = "../common" }
+sc-executor-common = { version = "0.8", path = "../common" }
 sp-wasm-interface = { version = "2.0.0", path = "../../../primitives/wasm-interface" }
 sp-runtime-interface = { version = "2.0.0", path = "../../../primitives/runtime-interface" }
 sp-core = { version = "2.0.0", path = "../../../primitives/core" }
-sp-externalities = { version = "2.0.0", path = "../../../primitives/externalities" }
diff --git a/client/executor/wasmi/src/lib.rs b/client/executor/wasmi/src/lib.rs
index 7c6141d6c835f..c10698fea46ad 100644
--- a/client/executor/wasmi/src/lib.rs
+++ b/client/executor/wasmi/src/lib.rs
@@ -27,7 +27,7 @@ use wasmi::{
 	memory_units::Pages, RuntimeValue::{I32, I64, self},
 };
 use codec::{Encode, Decode};
-use sp_core::{sandbox as sandbox_primitives, traits::Externalities};
+use sp_core::sandbox as sandbox_primitives;
 use log::{error, trace};
 use parity_wasm::elements::{deserialize_buffer, DataSegment, Instruction, Module as RawModule};
 use sp_wasm_interface::{
@@ -381,7 +381,6 @@ fn get_heap_base(module: &ModuleRef) -> Result<u32, Error> {
 
 /// Call a given method in the given wasm-module runtime.
 fn call_in_wasm_module(
-	ext: &mut dyn Externalities,
 	module_instance: &ModuleRef,
 	method: &str,
 	data: &[u8],
@@ -410,13 +409,10 @@ fn call_in_wasm_module(
 	let offset = fec.allocate_memory(data.len() as u32)?;
 	fec.write_memory(offset, data)?;
 
-	let result = sp_externalities::set_and_run_with_externalities(
-		ext,
-		|| module_instance.invoke_export(
-			method,
-			&[I32(u32::from(offset) as i32), I32(data.len() as i32)],
-			&mut fec,
-		),
+	let result = module_instance.invoke_export(
+		method,
+		&[I32(u32::from(offset) as i32), I32(data.len() as i32)],
+		&mut fec,
 	);
 
 	match result {
@@ -599,7 +595,6 @@ impl WasmRuntime for WasmiRuntime {
 
 	fn call(
 		&mut self,
-		ext: &mut dyn Externalities,
 		method: &str,
 		data: &[u8],
 	) -> Result<Vec<u8>, Error> {
@@ -612,7 +607,6 @@ impl WasmRuntime for WasmiRuntime {
 				e
 			})?;
 		call_in_wasm_module(
-			ext,
 			&self.instance,
 			method,
 			data,
diff --git a/client/executor/wasmtime/Cargo.toml b/client/executor/wasmtime/Cargo.toml
index 0d6bede016e66..44912086eaaed 100644
--- a/client/executor/wasmtime/Cargo.toml
+++ b/client/executor/wasmtime/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "sc-executor-wasmtime"
-version = "2.0.0"
+version = "0.8.0"
 authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2018"
 
@@ -9,11 +9,10 @@ log = "0.4.8"
 wasmi = "0.6.2"
 parity-wasm = "0.41.0"
 codec = { package = "parity-scale-codec", version = "1.0.0" }
-sc-executor-common = { version = "2.0.0", path = "../common" }
+sc-executor-common = { version = "0.8", path = "../common" }
 sp-wasm-interface = { version = "2.0.0", path = "../../../primitives/wasm-interface" }
 sp-runtime-interface = { version = "2.0.0", path = "../../../primitives/runtime-interface" }
 sp-core = { version = "2.0.0", path = "../../../primitives/core" }
-sp-externalities = { version = "2.0.0", path = "../../../primitives/externalities" }
 
 cranelift-codegen = "0.50"
 cranelift-entity = "0.50"
diff --git a/client/executor/wasmtime/src/runtime.rs b/client/executor/wasmtime/src/runtime.rs
index ae4739d1f1d3f..f9b1b6209c3b7 100644
--- a/client/executor/wasmtime/src/runtime.rs
+++ b/client/executor/wasmtime/src/runtime.rs
@@ -24,7 +24,6 @@ use sc_executor_common::{
 	error::{Error, Result, WasmError},
 	wasm_runtime::WasmRuntime,
 };
-use sp_core::traits::Externalities;
 use sp_wasm_interface::{Pointer, WordSize, Function};
 use sp_runtime_interface::unpack_ptr_and_len;
 
@@ -70,11 +69,10 @@ impl WasmRuntime for WasmtimeRuntime {
 		&self.host_functions
 	}
 
-	fn call(&mut self, ext: &mut dyn Externalities, method: &str, data: &[u8]) -> Result<Vec<u8>> {
+	fn call(&mut self, method: &str, data: &[u8]) -> Result<Vec<u8>> {
 		call_method(
 			&mut self.context,
 			&mut self.module,
-			ext,
 			method,
 			data,
 			self.heap_pages,
@@ -146,7 +144,6 @@ fn create_compiled_unit(
 fn call_method(
 	context: &mut Context,
 	module: &mut CompiledModule,
-	ext: &mut dyn Externalities,
 	method: &str,
 	data: &[u8],
 	heap_pages: u32,
@@ -176,11 +173,9 @@ fn call_method(
 	let args = [RuntimeValue::I32(u32::from(data_ptr) as i32), RuntimeValue::I32(data_len as i32)];
 
 	// Invoke the function in the runtime.
-	let outcome = sp_externalities::set_and_run_with_externalities(ext, || {
-		context
-			.invoke(&mut instance, method, &args[..])
-			.map_err(|e| Error::Other(format!("error calling runtime: {}", e)))
-	})?;
+	let outcome = context
+		.invoke(&mut instance, method, &args[..])
+		.map_err(|e| Error::Other(format!("error calling runtime: {}", e)))?;
 	let trap_error = reset_env_state_and_take_trap(context, None)?;
 	let (output_ptr, output_len) = match outcome {
 		ActionOutcome::Returned { values } => match values.as_slice() {
diff --git a/client/finality-grandpa/Cargo.toml b/client/finality-grandpa/Cargo.toml
index 9f90834e0df3c..2c0a10857c7f1 100644
--- a/client/finality-grandpa/Cargo.toml
+++ b/client/finality-grandpa/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "sc-finality-grandpa"
-version = "2.0.0"
+version = "0.8.0"
 authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2018"
 
@@ -13,6 +13,7 @@ log = "0.4.8"
 parking_lot = "0.9.0"
 rand = "0.7.2"
 parity-scale-codec = { version = "1.0.0", features = ["derive"] }
+sp-arithmetic = { version = "2.0.0", path = "../../primitives/arithmetic" }
 sp-runtime = { version = "2.0.0", path = "../../primitives/runtime" }
 sp-consensus = { version = "0.8", path = "../../primitives/consensus/common" }
 sp-core = { version = "2.0.0", path = "../../primitives/core" }
@@ -20,23 +21,23 @@ sc-telemetry = { version = "2.0.0", path = "../telemetry" }
 sc-keystore = { version = "2.0.0", path = "../keystore" }
 serde_json = "1.0.41"
 sc-client-api = { version = "2.0.0", path = "../api" }
-sc-client = { version = "2.0.0", path = "../" }
+sc-client = { version = "0.8", path = "../" }
 sp-inherents = { version = "2.0.0", path = "../../primitives/inherents" }
 sp-blockchain = { version = "2.0.0", path = "../../primitives/blockchain" }
 sc-network = { version = "0.8", path = "../network" }
-sc-network-gossip = { version = "2.0.0", path = "../network-gossip" }
+sc-network-gossip = { version = "0.8", path = "../network-gossip" }
 sp-finality-tracker = { version = "2.0.0", path = "../../primitives/finality-tracker" }
 sp-finality-grandpa = { version = "2.0.0", path = "../../primitives/finality-grandpa" }
-finality-grandpa = { version = "0.10.1", features = ["derive-codec"] }
+finality-grandpa = { version = "0.10.3", features = ["derive-codec"] }
 
 [dev-dependencies]
-finality-grandpa = { version = "0.10.1", features = ["derive-codec", "test-helpers"] }
+finality-grandpa = { version = "0.10.3", features = ["derive-codec", "test-helpers"] }
 sc-network = { version = "0.8", path = "../network" }
-sc-network-test = { version = "2.0.0", path = "../network/test" }
+sc-network-test = { version = "0.8.0", path = "../network/test" }
 sp-keyring = { version = "2.0.0", path = "../../primitives/keyring" }
 substrate-test-runtime-client = { version = "2.0.0",  path = "../../test-utils/runtime/client" }
 sp-consensus-babe = { version = "0.8", path = "../../primitives/consensus/babe" }
-sp-state-machine = { version = "2.0.0", path = "../../primitives/state-machine" }
+sp-state-machine = { version = "0.8", path = "../../primitives/state-machine" }
 env_logger = "0.7.0"
 tokio = "0.1.22"
 tempfile = "3.1.0"
diff --git a/client/finality-grandpa/src/communication/gossip.rs b/client/finality-grandpa/src/communication/gossip.rs
index 1135cc4f8674f..ec74393d80ff1 100644
--- a/client/finality-grandpa/src/communication/gossip.rs
+++ b/client/finality-grandpa/src/communication/gossip.rs
@@ -83,15 +83,15 @@
 //! We only send polite messages to peers,
 
 use sp_runtime::traits::{NumberFor, Block as BlockT, Zero};
-use sc_network_gossip::{GossipEngine, MessageIntent, ValidatorContext};
+use sc_network_gossip::{MessageIntent, ValidatorContext};
 use sc_network::{config::Roles, PeerId, ReputationChange};
 use parity_scale_codec::{Encode, Decode};
 use sp_finality_grandpa::AuthorityId;
 
 use sc_telemetry::{telemetry, CONSENSUS_DEBUG};
-use log::{trace, debug, warn};
+use log::{trace, debug};
 use futures::prelude::*;
-use futures::sync::mpsc;
+use futures03::channel::mpsc;
 use rand::seq::SliceRandom;
 
 use crate::{environment, CatchUp, CompactCommit, SignedMessage};
@@ -1178,7 +1178,7 @@ impl<Block: BlockT> GossipValidator<Block> {
 	pub(super) fn new(
 		config: crate::Config,
 		set_state: environment::SharedVoterSetState<Block>,
-	) -> (GossipValidator<Block>, ReportStream)	{
+	) -> (GossipValidator<Block>, mpsc::UnboundedReceiver<PeerReport>)	{
 		let (tx, rx) = mpsc::unbounded();
 		let val = GossipValidator {
 			inner: parking_lot::RwLock::new(Inner::new(config)),
@@ -1186,7 +1186,7 @@ impl<Block: BlockT> GossipValidator<Block> {
 			report_sender: tx,
 		};
 
-		(val, ReportStream { reports: rx })
+		(val, rx)
 	}
 
 	/// Note a round in the current set has started.
@@ -1445,57 +1445,9 @@ impl<Block: BlockT> sc_network_gossip::Validator<Block> for GossipValidator<Bloc
 	}
 }
 
-struct PeerReport {
-	who: PeerId,
-	cost_benefit: ReputationChange,
-}
-
-// wrapper around a stream of reports.
-#[must_use = "The report stream must be consumed"]
-pub(super) struct ReportStream {
-	reports: mpsc::UnboundedReceiver<PeerReport>,
-}
-
-impl ReportStream {
-	/// Consume the report stream, converting it into a future that
-	/// handles all reports.
-	pub(super) fn consume<B>(self, net: GossipEngine<B>)
-		-> impl Future<Item=(),Error=()> + Send + 'static
-	where
-		B: BlockT,
-	{
-		ReportingTask {
-			reports: self.reports,
-			net,
-		}
-	}
-}
-
-/// A future for reporting peers.
-#[must_use = "Futures do nothing unless polled"]
-struct ReportingTask<B: BlockT> {
-	reports: mpsc::UnboundedReceiver<PeerReport>,
-	net: GossipEngine<B>,
-}
-
-impl<B: BlockT> Future for ReportingTask<B> {
-	type Item = ();
-	type Error = ();
-
-	fn poll(&mut self) -> Poll<(), ()> {
-		loop {
-			match self.reports.poll() {
-				Err(_) => {
-					warn!(target: "afg", "Report stream terminated unexpectedly");
-					return Ok(Async::Ready(()))
-				}
-				Ok(Async::Ready(None)) => return Ok(Async::Ready(())),
-				Ok(Async::Ready(Some(PeerReport { who, cost_benefit }))) =>
-					self.net.report(who, cost_benefit),
-				Ok(Async::NotReady) => return Ok(Async::NotReady),
-			}
-		}
-	}
+pub(super) struct PeerReport {
+	pub who: PeerId,
+	pub cost_benefit: ReputationChange,
 }
 
 #[cfg(test)]
diff --git a/client/finality-grandpa/src/communication/mod.rs b/client/finality-grandpa/src/communication/mod.rs
index b65f340652542..7723047d1b423 100644
--- a/client/finality-grandpa/src/communication/mod.rs
+++ b/client/finality-grandpa/src/communication/mod.rs
@@ -27,13 +27,19 @@
 //! In the future, there will be a fallback for allowing sending the same message
 //! under certain conditions that are used to un-stick the protocol.
 
-use std::sync::Arc;
+use futures::{prelude::*, sync::mpsc};
+use futures03::{
+	channel::mpsc as mpsc03,
+	compat::Compat,
+	future::{Future as Future03},
+	stream::StreamExt,
+};
+use log::{debug, trace};
+use parking_lot::Mutex;
+use std::{pin::Pin, sync::Arc, task::{Context, Poll as Poll03}};
 
-use futures::{prelude::*, future::Executor as _, sync::mpsc};
-use futures03::{compat::Compat, stream::StreamExt, future::FutureExt as _, future::TryFutureExt as _};
 use finality_grandpa::Message::{Prevote, Precommit, PrimaryPropose};
 use finality_grandpa::{voter, voter_set::VoterSet};
-use log::{debug, trace};
 use sc_network::{NetworkService, ReputationChange};
 use sc_network_gossip::{GossipEngine, Network as GossipNetwork};
 use parity_scale_codec::{Encode, Decode};
@@ -47,7 +53,12 @@ use crate::{
 };
 use crate::environment::HasVoted;
 use gossip::{
-	GossipMessage, FullCatchUpMessage, FullCommitMessage, VoteMessage, GossipValidator
+	FullCatchUpMessage,
+	FullCommitMessage,
+	GossipMessage,
+	GossipValidator,
+	PeerReport,
+	VoteMessage,
 };
 use sp_finality_grandpa::{
 	AuthorityPair, AuthorityId, AuthoritySignature, SetId as SetIdNumber, RoundNumber,
@@ -134,9 +145,31 @@ pub(crate) struct NetworkBridge<B: BlockT, N: Network<B>> {
 	service: N,
 	gossip_engine: GossipEngine<B>,
 	validator: Arc<GossipValidator<B>>,
+
+	/// Sender side of the neighbor packet channel.
+	///
+	/// Packets sent into this channel are processed by the `NeighborPacketWorker` and passed on to
+	/// the underlying `GossipEngine`.
 	neighbor_sender: periodic::NeighborPacketSender<B>,
+
+	/// `NeighborPacketWorker` processing packets sent through the `NeighborPacketSender`.
+	//
+	// `NetworkBridge` is required to be clonable, thus one needs to be able to clone its children,
+	// thus one has to wrap neighor_packet_worker with an `Arc` `Mutex`.
+	neighbor_packet_worker: Arc<Mutex<periodic::NeighborPacketWorker<B>>>,
+
+	/// Receiver side of the peer report stream populated by the gossip validator, forwarded to the
+	/// gossip engine.
+	//
+	// `NetworkBridge` is required to be clonable, thus one needs to be able to clone its children,
+	// thus one has to wrap gossip_validator_report_stream with an `Arc` `Mutex`. Given that it is
+	// just an `UnboundedReceiver`, one could also switch to a multi-producer-*multi*-consumer
+	// channel implementation.
+	gossip_validator_report_stream: Arc<Mutex<mpsc03::UnboundedReceiver<PeerReport>>>,
 }
 
+impl<B: BlockT, N: Network<B>> Unpin for NetworkBridge<B, N> {}
+
 impl<B: BlockT, N: Network<B>> NetworkBridge<B, N> {
 	/// Create a new NetworkBridge to the given NetworkService. Returns the service
 	/// handle.
@@ -147,7 +180,6 @@ impl<B: BlockT, N: Network<B>> NetworkBridge<B, N> {
 		config: crate::Config,
 		set_state: crate::environment::SharedVoterSetState<B>,
 		executor: &impl futures03::task::Spawn,
-		on_exit: impl futures03::Future<Output = ()> + Clone + Send + Unpin + 'static,
 	) -> Self {
 		let (validator, report_stream) = GossipValidator::new(
 			config,
@@ -195,16 +227,16 @@ impl<B: BlockT, N: Network<B>> NetworkBridge<B, N> {
 			}
 		}
 
-		let (rebroadcast_job, neighbor_sender) = periodic::neighbor_packet_worker(gossip_engine.clone());
-		let reporting_job = report_stream.consume(gossip_engine.clone());
-
-		let bridge = NetworkBridge { service, gossip_engine, validator, neighbor_sender };
+		let (neighbor_packet_worker, neighbor_packet_sender) = periodic::NeighborPacketWorker::new();
 
-		let executor = Compat::new(executor);
-		executor.execute(Box::new(rebroadcast_job.select(on_exit.clone().map(Ok).compat()).then(|_| Ok(()))))
-			.expect("failed to spawn grandpa rebroadcast job task");
-		executor.execute(Box::new(reporting_job.select(on_exit.clone().map(Ok).compat()).then(|_| Ok(()))))
-			.expect("failed to spawn grandpa reporting job task");
+		let bridge = NetworkBridge {
+			service,
+			gossip_engine,
+			validator,
+			neighbor_sender: neighbor_packet_sender,
+			neighbor_packet_worker: Arc::new(Mutex::new(neighbor_packet_worker)),
+			gossip_validator_report_stream: Arc::new(Mutex::new(report_stream)),
+		};
 
 		bridge
 	}
@@ -391,6 +423,38 @@ impl<B: BlockT, N: Network<B>> NetworkBridge<B, N> {
 	}
 }
 
+impl<B: BlockT, N: Network<B>> Future03 for NetworkBridge<B, N> {
+	type Output = Result<(), Error>;
+
+	fn poll(self: Pin<&mut Self>, cx: &mut Context) -> Poll03<Self::Output> {
+		loop {
+			match self.neighbor_packet_worker.lock().poll_next_unpin(cx) {
+				Poll03::Ready(Some((to, packet))) => {
+					self.gossip_engine.send_message(to, packet.encode());
+				},
+				Poll03::Ready(None) => return Poll03::Ready(
+					Err(Error::Network("Neighbor packet worker stream closed.".into()))
+				),
+				Poll03::Pending => break,
+			}
+		}
+
+		loop {
+			match self.gossip_validator_report_stream.lock().poll_next_unpin(cx) {
+				Poll03::Ready(Some(PeerReport { who, cost_benefit })) => {
+					self.gossip_engine.report(who, cost_benefit);
+				},
+				Poll03::Ready(None) => return Poll03::Ready(
+					Err(Error::Network("Gossip validator report stream closed.".into()))
+				),
+				Poll03::Pending => break,
+			}
+		}
+
+		Poll03::Pending
+	}
+}
+
 fn incoming_global<B: BlockT>(
 	mut gossip_engine: GossipEngine<B>,
 	topic: B::Hash,
@@ -530,6 +594,8 @@ impl<B: BlockT, N: Network<B>> Clone for NetworkBridge<B, N> {
 			gossip_engine: self.gossip_engine.clone(),
 			validator: Arc::clone(&self.validator),
 			neighbor_sender: self.neighbor_sender.clone(),
+			neighbor_packet_worker: self.neighbor_packet_worker.clone(),
+			gossip_validator_report_stream: self.gossip_validator_report_stream.clone(),
 		}
 	}
 }
diff --git a/client/finality-grandpa/src/communication/periodic.rs b/client/finality-grandpa/src/communication/periodic.rs
index a31203104b61f..d5c8c1e0b856c 100644
--- a/client/finality-grandpa/src/communication/periodic.rs
+++ b/client/finality-grandpa/src/communication/periodic.rs
@@ -16,21 +16,16 @@
 
 //! Periodic rebroadcast of neighbor packets.
 
-use std::time::{Instant, Duration};
-
-use parity_scale_codec::Encode;
-use futures::prelude::*;
-use futures::sync::mpsc;
 use futures_timer::Delay;
-use futures03::future::{FutureExt as _, TryFutureExt as _};
-use log::{debug, warn};
+use futures03::{channel::mpsc, future::{FutureExt as _}, prelude::*, ready, stream::Stream};
+use log::debug;
+use std::{pin::Pin, task::{Context, Poll}, time::{Instant, Duration}};
 
 use sc_network::PeerId;
-use sc_network_gossip::GossipEngine;
 use sp_runtime::traits::{NumberFor, Block as BlockT};
 use super::gossip::{NeighborPacket, GossipMessage};
 
-// how often to rebroadcast, if no other
+// How often to rebroadcast, in cases where no new packets are created.
 const REBROADCAST_AFTER: Duration = Duration::from_secs(2 * 60);
 
 fn rebroadcast_instant() -> Instant {
@@ -56,56 +51,65 @@ impl<B: BlockT> NeighborPacketSender<B> {
 	}
 }
 
-/// Does the work of sending neighbor packets, asynchronously.
-///
-/// It may rebroadcast the last neighbor packet periodically when no
-/// progress is made.
-pub(super) fn neighbor_packet_worker<B>(net: GossipEngine<B>) -> (
-	impl Future<Item = (), Error = ()> + Send + 'static,
-	NeighborPacketSender<B>,
-) where
-	B: BlockT,
-{
-	let mut last = None;
-	let (tx, mut rx) = mpsc::unbounded::<(Vec<PeerId>, NeighborPacket<NumberFor<B>>)>();
-	let mut delay = Delay::new(REBROADCAST_AFTER);
-
-	let work = futures::future::poll_fn(move || {
-		loop {
-			match rx.poll().expect("unbounded receivers do not error; qed") {
-				Async::Ready(None) => return Ok(Async::Ready(())),
-				Async::Ready(Some((to, packet))) => {
-					// send to peers.
-					net.send_message(to.clone(), GossipMessage::<B>::from(packet.clone()).encode());
-
-					// rebroadcasting network.
-					delay.reset(rebroadcast_instant());
-					last = Some((to, packet));
-				}
-				Async::NotReady => break,
-			}
-		}
+/// NeighborPacketWorker is listening on a channel for new neighbor packets being produced by
+/// components within `finality-grandpa` and forwards those packets to the underlying
+/// `NetworkEngine` through the `NetworkBridge` that it is being polled by (see `Stream`
+/// implementation). Periodically it sends out the last packet in cases where no new ones arrive.
+pub(super) struct NeighborPacketWorker<B: BlockT> {
+	last: Option<(Vec<PeerId>, NeighborPacket<NumberFor<B>>)>,
+	delay: Delay,
+	rx: mpsc::UnboundedReceiver<(Vec<PeerId>, NeighborPacket<NumberFor<B>>)>,
+}
+
+impl<B: BlockT> Unpin for NeighborPacketWorker<B> {}
+
+impl<B: BlockT> NeighborPacketWorker<B> {
+	pub(super) fn new() -> (Self, NeighborPacketSender<B>){
+		let (tx, rx) = mpsc::unbounded::<(Vec<PeerId>, NeighborPacket<NumberFor<B>>)>();
+		let delay = Delay::new(REBROADCAST_AFTER);
+
+		(NeighborPacketWorker {
+			last: None,
+			delay,
+			rx,
+		}, NeighborPacketSender(tx))
+	}
+}
 
-		// has to be done in a loop because it needs to be polled after
-		// re-scheduling.
-		loop {
-			match (&mut delay).unit_error().compat().poll() {
-				Err(e) => {
-					warn!(target: "afg", "Could not rebroadcast neighbor packets: {:?}", e);
-					delay.reset(rebroadcast_instant());
-				}
-				Ok(Async::Ready(())) => {
-					delay.reset(rebroadcast_instant());
-
-					if let Some((ref to, ref packet)) = last {
-						// send to peers.
-						net.send_message(to.clone(), GossipMessage::<B>::from(packet.clone()).encode());
-					}
-				}
-				Ok(Async::NotReady) => return Ok(Async::NotReady),
+impl <B: BlockT> Stream for NeighborPacketWorker<B> {
+	type Item = (Vec<PeerId>, GossipMessage<B>);
+
+	fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context) -> Poll<Option<Self::Item>>
+	{
+		let this = &mut *self;
+		match this.rx.poll_next_unpin(cx) {
+			Poll::Ready(None) => return Poll::Ready(None),
+			Poll::Ready(Some((to, packet))) => {
+				this.delay.reset(rebroadcast_instant());
+				this.last = Some((to.clone(), packet.clone()));
+
+				return Poll::Ready(Some((to, GossipMessage::<B>::from(packet.clone()))));
 			}
+			// Don't return yet, maybe the timer fired.
+			Poll::Pending => {},
+		};
+
+		ready!(this.delay.poll_unpin(cx));
+
+		// Getting this far here implies that the timer fired.
+
+		this.delay.reset(rebroadcast_instant());
+
+		// Make sure the underlying task is scheduled for wake-up.
+		//
+		// Note: In case poll_unpin is called after the resetted delay fires again, this
+		// will drop one tick. Deemed as very unlikely and also not critical.
+		while let Poll::Ready(()) = this.delay.poll_unpin(cx) {};
+
+		if let Some((ref to, ref packet)) = this.last {
+			return Poll::Ready(Some((to.clone(), GossipMessage::<B>::from(packet.clone()))));
 		}
-	});
 
-	(work, NeighborPacketSender(tx))
+		return Poll::Pending;
+	}
 }
diff --git a/client/finality-grandpa/src/communication/tests.rs b/client/finality-grandpa/src/communication/tests.rs
index a016940a05652..c104af0339260 100644
--- a/client/finality-grandpa/src/communication/tests.rs
+++ b/client/finality-grandpa/src/communication/tests.rs
@@ -172,7 +172,6 @@ fn make_test_network(executor: &impl futures03::task::Spawn) -> (
 		config(),
 		voter_set_state(),
 		executor,
-		Exit,
 	);
 
 	(
diff --git a/client/finality-grandpa/src/environment.rs b/client/finality-grandpa/src/environment.rs
index d708e00bfd444..372229001dd19 100644
--- a/client/finality-grandpa/src/environment.rs
+++ b/client/finality-grandpa/src/environment.rs
@@ -412,7 +412,7 @@ for Environment<B, E, Block, N, RA, SC, VR>
 where
 	Block: 'static,
 	B: Backend<Block> + 'static,
-	E: CallExecutor<Block> + Send + Sync + 'static,
+	E: CallExecutor<Block> + Send + Sync,
  	N: NetworkT<Block> + 'static + Send,
 	SC: SelectChain<Block> + 'static,
 	VR: VotingRule<Block, Client<B, E, Block, RA>>,
diff --git a/client/finality-grandpa/src/lib.rs b/client/finality-grandpa/src/lib.rs
index 809e0ab88a3a3..071214961f9a1 100644
--- a/client/finality-grandpa/src/lib.rs
+++ b/client/finality-grandpa/src/lib.rs
@@ -53,6 +53,7 @@
 //! included in the newly-finalized chain.
 
 use futures::prelude::*;
+use futures03::{StreamExt, future::ready};
 use log::{debug, error, info};
 use futures::sync::mpsc;
 use sc_client_api::{BlockchainEvents, CallExecutor, backend::{AuxStore, Backend}, ExecutionStrategy};
@@ -95,7 +96,7 @@ pub use justification::GrandpaJustification;
 pub use light_import::light_block_import;
 pub use observer::run_grandpa_observer;
 pub use voting_rule::{
-	BeforeBestBlock, ThreeQuartersOfTheUnfinalizedChain, VotingRule, VotingRulesBuilder
+	BeforeBestBlockBy, ThreeQuartersOfTheUnfinalizedChain, VotingRule, VotingRulesBuilder
 };
 
 use aux_schema::PersistentData;
@@ -371,7 +372,7 @@ pub trait GenesisAuthoritySetProvider<Block: BlockT> {
 impl<B, E, Block: BlockT, RA> GenesisAuthoritySetProvider<Block> for Client<B, E, Block, RA>
 	where
 		B: Backend<Block> + Send + Sync + 'static,
-		E: CallExecutor<Block> + 'static + Clone + Send + Sync,
+		E: CallExecutor<Block> + Send + Sync,
 		RA: Send + Sync,
 {
 	fn get(&self) -> Result<AuthorityList, ClientError> {
@@ -407,7 +408,7 @@ pub fn block_import<B, E, Block: BlockT, RA, SC>(
 	), ClientError>
 where
 	B: Backend<Block> + 'static,
-	E: CallExecutor<Block> + 'static + Clone + Send + Sync,
+	E: CallExecutor<Block> + Send + Sync,
 	RA: Send + Sync,
 	SC: SelectChain<Block>,
 	Client<B, E, Block, RA>: AuxStore,
@@ -535,7 +536,7 @@ pub struct GrandpaParams<B, E, Block: BlockT, N, RA, SC, VR, X, Sp> {
 	/// Handle to a future that will resolve on exit.
 	pub on_exit: X,
 	/// If supplied, can be used to hook on telemetry connection established events.
-	pub telemetry_on_connect: Option<mpsc::UnboundedReceiver<()>>,
+	pub telemetry_on_connect: Option<futures03::channel::mpsc::UnboundedReceiver<()>>,
 	/// A voting rule used to potentially restrict target votes.
 	pub voting_rule: VR,
 	/// How to spawn background tasks.
@@ -583,7 +584,6 @@ pub fn run_grandpa_voter<B, E, Block: BlockT, N, RA, SC, VR, X, Sp>(
 		config.clone(),
 		persistent_data.set_state.clone(),
 		&executor,
-		on_exit.clone(),
 	);
 
 	register_finality_tracker_inherent_data_provider(client.clone(), &inherent_data_providers)?;
@@ -608,9 +608,10 @@ pub fn run_grandpa_voter<B, E, Block: BlockT, N, RA, SC, VR, X, Sp>(
 							.expect("authorities is always at least an empty vector; elements are always of type string")
 					}
 				);
-				Ok(())
+				ready(())
 			})
-			.then(|_| -> Result<(), ()> { Ok(()) });
+			.unit_error()
+			.compat();
 		futures::future::Either::A(events)
 	} else {
 		futures::future::Either::B(futures::future::empty())
@@ -648,12 +649,13 @@ struct VoterWork<B, E, Block: BlockT, N: NetworkT<Block>, RA, SC, VR> {
 	voter: Box<dyn Future<Item = (), Error = CommandOrError<Block::Hash, NumberFor<Block>>> + Send>,
 	env: Arc<Environment<B, E, Block, N, RA, SC, VR>>,
 	voter_commands_rx: mpsc::UnboundedReceiver<VoterCommand<Block::Hash, NumberFor<Block>>>,
+	network: futures03::compat::Compat<NetworkBridge<Block, N>>,
 }
 
 impl<B, E, Block, N, RA, SC, VR> VoterWork<B, E, Block, N, RA, SC, VR>
 where
 	Block: BlockT,
- 	N: NetworkT<Block> + Sync,
+	N: NetworkT<Block> + Sync,
 	NumberFor<Block>: BlockNumberOps,
 	RA: 'static + Send + Sync,
 	E: CallExecutor<Block> + Send + Sync + 'static,
@@ -679,7 +681,7 @@ where
 			voting_rule,
 			voters: Arc::new(voters),
 			config,
-			network,
+			network: network.clone(),
 			set_id: persistent_data.authority_set.set_id(),
 			authority_set: persistent_data.authority_set.clone(),
 			consensus_changes: persistent_data.consensus_changes.clone(),
@@ -692,6 +694,7 @@ where
 			voter: Box::new(futures::empty()) as Box<_>,
 			env,
 			voter_commands_rx,
+			network: futures03::future::TryFutureExt::compat(network),
 		};
 		work.rebuild_voter();
 		work
@@ -829,7 +832,7 @@ where
 impl<B, E, Block, N, RA, SC, VR> Future for VoterWork<B, E, Block, N, RA, SC, VR>
 where
 	Block: BlockT,
- 	N: NetworkT<Block> + Sync,
+	N: NetworkT<Block> + Sync,
 	NumberFor<Block>: BlockNumberOps,
 	RA: 'static + Send + Sync,
 	E: CallExecutor<Block> + Send + Sync + 'static,
@@ -876,6 +879,15 @@ where
 			}
 		}
 
+		match self.network.poll() {
+			Ok(Async::NotReady) => {},
+			Ok(Async::Ready(())) => {
+				// the network bridge future should never conclude.
+				return Ok(Async::Ready(()))
+			}
+			e @ Err(_) => return e,
+		};
+
 		Ok(Async::NotReady)
 	}
 }
diff --git a/client/finality-grandpa/src/observer.rs b/client/finality-grandpa/src/observer.rs
index 3dbb2aff6a9cf..989a1e1655e8d 100644
--- a/client/finality-grandpa/src/observer.rs
+++ b/client/finality-grandpa/src/observer.rs
@@ -67,7 +67,7 @@ fn grandpa_observer<B, E, Block: BlockT, RA, S, F>(
 ) -> impl Future<Item=(), Error=CommandOrError<Block::Hash, NumberFor<Block>>> where
 	NumberFor<Block>: BlockNumberOps,
 	B: Backend<Block>,
-	E: CallExecutor<Block> + Send + Sync,
+	E: CallExecutor<Block> + Send + Sync + 'static,
 	RA: Send + Sync,
 	S: Stream<
 		Item = CommunicationIn<Block>,
@@ -178,7 +178,6 @@ pub fn run_grandpa_observer<B, E, Block: BlockT, N, RA, SC, Sp>(
 		config.clone(),
 		persistent_data.set_state.clone(),
 		&executor,
-		on_exit.clone(),
 	);
 
 	let observer_work = ObserverWork::new(
diff --git a/client/finality-grandpa/src/tests.rs b/client/finality-grandpa/src/tests.rs
index 4ad08c8868f27..9ad12c6c317ad 100644
--- a/client/finality-grandpa/src/tests.rs
+++ b/client/finality-grandpa/src/tests.rs
@@ -25,7 +25,7 @@ use sc_network_test::{
 use sc_network::config::{ProtocolConfig, Roles, BoxFinalityProofRequestBuilder};
 use parking_lot::Mutex;
 use futures_timer::Delay;
-use futures03::{StreamExt as _, TryStreamExt as _};
+use futures03::TryStreamExt as _;
 use tokio::runtime::current_thread;
 use sp_keyring::Ed25519Keyring;
 use sc_client::LongestChain;
@@ -287,12 +287,10 @@ impl ApiExt<Block> for RuntimeApi {
 		unimplemented!("Not required for testing!")
 	}
 
-	fn into_storage_changes<
-		T: sp_api::ChangesTrieStorage<sp_api::HasherFor<Block>, sp_api::NumberFor<Block>>
-	>(
+	fn into_storage_changes(
 		&self,
 		_: &Self::StateBackend,
-		_: Option<&T>,
+		_: Option<&sp_api::ChangesTrieState<sp_api::HasherFor<Block>, sp_api::NumberFor<Block>>>,
 		_: <Block as sp_api::BlockT>::Hash,
 	) -> std::result::Result<sp_api::StorageChanges<Self::StateBackend, Block>, String>
 		where Self: Sized
@@ -1272,7 +1270,6 @@ fn voter_persists_its_votes() {
 			config.clone(),
 			set_state,
 			&threads_pool,
-			Exit,
 		);
 
 		let (round_rx, round_tx) = network.round_communication(
@@ -1677,7 +1674,6 @@ fn grandpa_environment_respects_voting_rules() {
 			config.clone(),
 			set_state.clone(),
 			&threads_pool,
-			Exit,
 		);
 
 		Environment {
@@ -1694,8 +1690,8 @@ fn grandpa_environment_respects_voting_rules() {
 		}
 	};
 
-	// add 20 blocks
-	peer.push_blocks(20, false);
+	// add 21 blocks
+	peer.push_blocks(21, false);
 
 	// create an environment with no voting rule restrictions
 	let unrestricted_env = environment(Box::new(()));
@@ -1716,38 +1712,38 @@ fn grandpa_environment_respects_voting_rules() {
 		unrestricted_env.best_chain_containing(
 			peer.client().info().finalized_hash
 		).unwrap().1,
-		20,
+		21,
 	);
 
-	// both the other environments should return block 15, which is 3/4 of the
+	// both the other environments should return block 16, which is 3/4 of the
 	// way in the unfinalized chain
 	assert_eq!(
 		three_quarters_env.best_chain_containing(
 			peer.client().info().finalized_hash
 		).unwrap().1,
-		15,
+		16,
 	);
 
 	assert_eq!(
 		default_env.best_chain_containing(
 			peer.client().info().finalized_hash
 		).unwrap().1,
-		15,
+		16,
 	);
 
-	// we finalize block 19 with block 20 being the best block
+	// we finalize block 19 with block 21 being the best block
 	peer.client().finalize_block(BlockId::Number(19), None, false).unwrap();
 
-	// the 3/4 environment should propose block 20 for voting
+	// the 3/4 environment should propose block 21 for voting
 	assert_eq!(
 		three_quarters_env.best_chain_containing(
 			peer.client().info().finalized_hash
 		).unwrap().1,
-		20,
+		21,
 	);
 
 	// while the default environment will always still make sure we don't vote
-	// on the best block
+	// on the best block (2 behind)
 	assert_eq!(
 		default_env.best_chain_containing(
 			peer.client().info().finalized_hash
@@ -1755,17 +1751,17 @@ fn grandpa_environment_respects_voting_rules() {
 		19,
 	);
 
-	// we finalize block 20 with block 20 being the best block
-	peer.client().finalize_block(BlockId::Number(20), None, false).unwrap();
+	// we finalize block 21 with block 21 being the best block
+	peer.client().finalize_block(BlockId::Number(21), None, false).unwrap();
 
 	// even though the default environment will always try to not vote on the
 	// best block, there's a hard rule that we can't cast any votes lower than
-	// the given base (#20).
+	// the given base (#21).
 	assert_eq!(
 		default_env.best_chain_containing(
 			peer.client().info().finalized_hash
 		).unwrap().1,
-		20,
+		21,
 	);
 }
 
diff --git a/client/finality-grandpa/src/voting_rule.rs b/client/finality-grandpa/src/voting_rule.rs
index 8ba52f30f7b0f..523a1b05cd488 100644
--- a/client/finality-grandpa/src/voting_rule.rs
+++ b/client/finality-grandpa/src/voting_rule.rs
@@ -70,30 +70,38 @@ impl<Block, B> VotingRule<Block, B> for () where
 /// A custom voting rule that guarantees that our vote is always behind the best
 /// block, in the best case exactly one block behind it.
 #[derive(Clone)]
-pub struct BeforeBestBlock;
-impl<Block, B> VotingRule<Block, B> for BeforeBestBlock where
+pub struct BeforeBestBlockBy<N>(N);
+impl<Block, B> VotingRule<Block, B> for BeforeBestBlockBy<NumberFor<Block>> where
 	Block: BlockT,
 	B: HeaderBackend<Block>,
 {
 	fn restrict_vote(
 		&self,
-		_backend: &B,
+		backend: &B,
 		_base: &Block::Header,
 		best_target: &Block::Header,
 		current_target: &Block::Header,
 	) -> Option<(Block::Hash, NumberFor<Block>)> {
+		use sp_arithmetic::traits::Saturating;
+
 		if current_target.number().is_zero() {
 			return None;
 		}
 
-		if current_target.number() == best_target.number() {
-			return Some((
-				current_target.parent_hash().clone(),
-				*current_target.number() - One::one(),
-			));
+		// find the target number restricted by this rule
+		let target_number = best_target.number().saturating_sub(self.0);
+
+		// our current target is already lower than this rule would restrict
+		if target_number >= *current_target.number() {
+			return None;
 		}
 
-		None
+		// find the block at the given target height
+		find_target(
+			backend,
+			target_number,
+			current_target,
+		)
 	}
 }
 
@@ -130,26 +138,43 @@ impl<Block, B> VotingRule<Block, B> for ThreeQuartersOfTheUnfinalizedChain where
 			return None;
 		}
 
-		let mut target_header = current_target.clone();
-		let mut target_hash = current_target.hash();
-
-		// walk backwards until we find the target block
-		loop {
-			if *target_header.number() < target_number {
-				unreachable!(
-					"we are traversing backwards from a known block; \
-					 blocks are stored contiguously; \
-					 qed"
-				);
-			}
-			if *target_header.number() == target_number {
-				return Some((target_hash, target_number));
-			}
-
-			target_hash = *target_header.parent_hash();
-			target_header = backend.header(BlockId::Hash(target_hash)).ok()?
-				.expect("Header known to exist due to the existence of one of its descendents; qed");
+		// find the block at the given target height
+		find_target(
+			backend,
+			target_number,
+			current_target,
+		)
+	}
+}
+
+// walk backwards until we find the target block
+fn find_target<Block, B>(
+	backend: &B,
+	target_number: NumberFor<Block>,
+	current_header: &Block::Header,
+) -> Option<(Block::Hash, NumberFor<Block>)> where
+	Block: BlockT,
+	B: HeaderBackend<Block>,
+{
+	let mut target_hash = current_header.hash();
+	let mut target_header = current_header.clone();
+
+	loop {
+		if *target_header.number() < target_number {
+			unreachable!(
+				"we are traversing backwards from a known block; \
+				 blocks are stored contiguously; \
+				 qed"
+			);
+		}
+
+		if *target_header.number() == target_number {
+			return Some((target_hash, target_number));
 		}
+
+		target_hash = *target_header.parent_hash();
+		target_header = backend.header(BlockId::Hash(target_hash)).ok()?
+			.expect("Header known to exist due to the existence of one of its descendents; qed");
 	}
 }
 
@@ -213,7 +238,7 @@ impl<Block, B> Default for VotingRulesBuilder<Block, B> where
 {
 	fn default() -> Self {
 		VotingRulesBuilder::new()
-			.add(BeforeBestBlock)
+			.add(BeforeBestBlockBy(2.into()))
 			.add(ThreeQuartersOfTheUnfinalizedChain)
 	}
 }
diff --git a/client/network-gossip/Cargo.toml b/client/network-gossip/Cargo.toml
index cf8d31c6d36e5..91c80e2213e00 100644
--- a/client/network-gossip/Cargo.toml
+++ b/client/network-gossip/Cargo.toml
@@ -1,7 +1,7 @@
 [package]
 description = "Gossiping for the Substrate network protocol"
 name = "sc-network-gossip"
-version = "2.0.0"
+version = "0.8.0"
 license = "GPL-3.0"
 authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2018"
diff --git a/client/network/Cargo.toml b/client/network/Cargo.toml
index d24f986f4cd21..f1d89f71b0ed1 100644
--- a/client/network/Cargo.toml
+++ b/client/network/Cargo.toml
@@ -25,13 +25,13 @@ rand = "0.7.2"
 libp2p = { version = "0.14.0-alpha.1", default-features = false, features = ["libp2p-websocket"] }
 fork-tree = { version = "2.0.0", path = "../../utils/fork-tree" }
 sp-consensus = { version = "0.8", path = "../../primitives/consensus/common" }
-sc-client = { version = "2.0.0", path = "../" }
+sc-client = { version = "0.8", path = "../" }
 sc-client-api = { version = "2.0.0", path = "../api" }
 sp-blockchain = { version = "2.0.0", path = "../../primitives/blockchain" }
 sp-runtime = { version = "2.0.0", path = "../../primitives/runtime" }
 sp-arithmetic = { version = "2.0.0", path = "../../primitives/arithmetic" }
 sp-core = { version = "2.0.0", path = "../../primitives/core" }
-sc-block-builder = { version = "2.0.0", path = "../block-builder" }
+sc-block-builder = { version = "0.8", path = "../block-builder" }
 codec = { package = "parity-scale-codec", version = "1.0.0", features = ["derive"] }
 sc-peerset = { version = "2.0.0", path = "../peerset" }
 serde = { version = "1.0.101", features = ["derive"] }
diff --git a/client/network/src/protocol.rs b/client/network/src/protocol.rs
index b712ebe515512..2aa29ea2793e3 100644
--- a/client/network/src/protocol.rs
+++ b/client/network/src/protocol.rs
@@ -1472,6 +1472,13 @@ impl<B: BlockT, S: NetworkSpecialization<B>, H: ExHashT> Protocol<B, S, H> {
 		who: PeerId,
 		request: message::RemoteReadRequest<B::Hash>,
 	) {
+		if request.keys.is_empty() {
+			debug!(target: "sync", "Invalid remote read request sent by {}", who);
+			self.behaviour.disconnect_peer(&who);
+			self.peerset_handle.report_peer(who, rep::BAD_MESSAGE);
+			return;
+		}
+
 		let keys_str = || match request.keys.len() {
 			1 => request.keys[0].to_hex::<String>(),
 			_ => format!(
@@ -1510,6 +1517,13 @@ impl<B: BlockT, S: NetworkSpecialization<B>, H: ExHashT> Protocol<B, S, H> {
 		who: PeerId,
 		request: message::RemoteReadChildRequest<B::Hash>,
 	) {
+		if request.keys.is_empty() {
+			debug!(target: "sync", "Invalid remote child read request sent by {}", who);
+			self.behaviour.disconnect_peer(&who);
+			self.peerset_handle.report_peer(who, rep::BAD_MESSAGE);
+			return;
+		}
+
 		let keys_str = || match request.keys.len() {
 			1 => request.keys[0].to_hex::<String>(),
 			_ => format!(
diff --git a/client/network/src/protocol/light_dispatch.rs b/client/network/src/protocol/light_dispatch.rs
index dd94abc2a46fd..bfa8daa181ca1 100644
--- a/client/network/src/protocol/light_dispatch.rs
+++ b/client/network/src/protocol/light_dispatch.rs
@@ -691,7 +691,7 @@ pub mod tests {
 	use crate::message::{self, BlockAttributes, Direction, FromBlock, RequestId};
 	use libp2p::PeerId;
 	use super::{REQUEST_TIMEOUT, LightDispatch, LightDispatchNetwork, RequestData, StorageProof};
-	use sp_test_primitives::{changes_trie_config, Block, Extrinsic, Header};
+	use sp_test_primitives::{Block, Extrinsic, Header};
 
 	struct DummyFetchChecker { ok: bool }
 
@@ -1095,7 +1095,11 @@ pub mod tests {
 
 		let (tx, response) = oneshot::channel();
 		light_dispatch.add_request(&mut network_interface, RequestData::RemoteChanges(RemoteChangesRequest {
-			changes_trie_config: changes_trie_config(),
+			changes_trie_configs: vec![sp_core::ChangesTrieConfigurationRange {
+				zero: (0, Default::default()),
+				end: None,
+				config: Some(sp_core::ChangesTrieConfiguration::new(4, 2)),
+			}],
 			first_block: (1, Default::default()),
 			last_block: (100, Default::default()),
 			max_block: (100, Default::default()),
diff --git a/client/network/src/protocol/sync.rs b/client/network/src/protocol/sync.rs
index 8929fc75f8dd8..a513d47ca4198 100644
--- a/client/network/src/protocol/sync.rs
+++ b/client/network/src/protocol/sync.rs
@@ -308,8 +308,8 @@ impl<B: BlockT> ChainSync<B> {
 			best_queued_hash: info.best_hash,
 			best_queued_number: info.best_number,
 			best_imported_number: info.best_number,
-			extra_finality_proofs: ExtraRequests::new(),
-			extra_justifications: ExtraRequests::new(),
+			extra_finality_proofs: ExtraRequests::new("finality proof"),
+			extra_justifications: ExtraRequests::new("justification"),
 			role,
 			required_block_attributes,
 			queue_blocks: Default::default(),
diff --git a/client/network/src/protocol/sync/extra_requests.rs b/client/network/src/protocol/sync/extra_requests.rs
index a0ea68af5f334..44b42b154fff2 100644
--- a/client/network/src/protocol/sync/extra_requests.rs
+++ b/client/network/src/protocol/sync/extra_requests.rs
@@ -18,7 +18,7 @@ use sp_blockchain::Error as ClientError;
 use crate::protocol::sync::{PeerSync, PeerSyncState};
 use fork_tree::ForkTree;
 use libp2p::PeerId;
-use log::{debug, warn};
+use log::{debug, trace, warn};
 use sp_runtime::traits::{Block as BlockT, NumberFor, Zero};
 use std::collections::{HashMap, HashSet, VecDeque};
 use std::time::{Duration, Instant};
@@ -48,10 +48,12 @@ pub(crate) struct ExtraRequests<B: BlockT> {
 	failed_requests: HashMap<ExtraRequest<B>, Vec<(PeerId, Instant)>>,
 	/// successful requests
 	importing_requests: HashSet<ExtraRequest<B>>,
+	/// the name of this type of extra request (useful for logging.)
+	request_type_name: &'static str,
 }
 
 impl<B: BlockT> ExtraRequests<B> {
-	pub(crate) fn new() -> Self {
+	pub(crate) fn new(request_type_name: &'static str) -> Self {
 		ExtraRequests {
 			tree: ForkTree::new(),
 			best_seen_finalized_number: Zero::zero(),
@@ -59,6 +61,7 @@ impl<B: BlockT> ExtraRequests<B> {
 			active_requests: HashMap::new(),
 			failed_requests: HashMap::new(),
 			importing_requests: HashSet::new(),
+			request_type_name,
 		}
 	}
 
@@ -113,11 +116,28 @@ impl<B: BlockT> ExtraRequests<B> {
 		// messages to chain sync.
 		if let Some(request) = self.active_requests.remove(&who) {
 			if let Some(r) = resp {
+				trace!(target: "sync", "Queuing import of {} from {:?} for {:?}",
+					self.request_type_name,
+					who,
+					request,
+				);
+
 				self.importing_requests.insert(request);
 				return Some((who, request.0, request.1, r))
+			} else {
+				trace!(target: "sync", "Empty {} response from {:?} for {:?}",
+					self.request_type_name,
+					who,
+					request,
+				);
 			}
 			self.failed_requests.entry(request).or_insert(Vec::new()).push((who, Instant::now()));
 			self.pending_requests.push_front(request);
+		} else {
+			trace!(target: "sync", "No active {} request to {:?}",
+				self.request_type_name,
+				who,
+			);
 		}
 		None
 	}
@@ -265,6 +285,13 @@ impl<'a, B: BlockT> Matcher<'a, B> {
 					continue
 				}
 				self.extras.active_requests.insert(peer.clone(), request);
+
+				trace!(target: "sync", "Sending {} request to {:?} for {:?}",
+					self.extras.request_type_name,
+					peer,
+					request,
+				);
+
 				return Some((peer.clone(), request))
 			}
 
@@ -293,7 +320,7 @@ mod tests {
 	#[test]
 	fn requests_are_processed_in_order() {
 		fn property(mut peers: ArbitraryPeers) {
-			let mut requests = ExtraRequests::<Block>::new();
+			let mut requests = ExtraRequests::<Block>::new("test");
 
 			let num_peers_available = peers.0.values()
 				.filter(|s| s.state == PeerSyncState::Available).count();
@@ -319,7 +346,7 @@ mod tests {
 	#[test]
 	fn new_roots_schedule_new_request() {
 		fn property(data: Vec<BlockNumber>) {
-			let mut requests = ExtraRequests::<Block>::new();
+			let mut requests = ExtraRequests::<Block>::new("test");
 			for (i, number) in data.into_iter().enumerate() {
 				let hash = [i as u8; 32].into();
 				let pending = requests.pending_requests.len();
@@ -336,7 +363,7 @@ mod tests {
 	#[test]
 	fn disconnecting_implies_rescheduling() {
 		fn property(mut peers: ArbitraryPeers) -> bool {
-			let mut requests = ExtraRequests::<Block>::new();
+			let mut requests = ExtraRequests::<Block>::new("test");
 
 			let num_peers_available = peers.0.values()
 				.filter(|s| s.state == PeerSyncState::Available).count();
@@ -371,7 +398,7 @@ mod tests {
 	#[test]
 	fn no_response_reschedules() {
 		fn property(mut peers: ArbitraryPeers) {
-			let mut requests = ExtraRequests::<Block>::new();
+			let mut requests = ExtraRequests::<Block>::new("test");
 
 			let num_peers_available = peers.0.values()
 				.filter(|s| s.state == PeerSyncState::Available).count();
@@ -404,7 +431,7 @@ mod tests {
 	fn request_is_rescheduled_when_earlier_block_is_finalized() {
 		let _ = ::env_logger::try_init();
 
-		let mut finality_proofs = ExtraRequests::<Block>::new();
+		let mut finality_proofs = ExtraRequests::<Block>::new("test");
 
 		let hash4 = [4; 32].into();
 		let hash5 = [5; 32].into();
@@ -442,7 +469,7 @@ mod tests {
 
 	#[test]
 	fn anecstor_roots_are_finalized_when_finality_notification_is_missed() {
-		let mut finality_proofs = ExtraRequests::<Block>::new();
+		let mut finality_proofs = ExtraRequests::<Block>::new("test");
 
 		let hash4 = [4; 32].into();
 		let hash5 = [5; 32].into();
diff --git a/client/network/src/service.rs b/client/network/src/service.rs
index 4e923a51a123e..9c9a87bb67e01 100644
--- a/client/network/src/service.rs
+++ b/client/network/src/service.rs
@@ -33,10 +33,10 @@ use std::task::Poll;
 use sp_consensus::import_queue::{ImportQueue, Link};
 use sp_consensus::import_queue::{BlockImportResult, BlockImportError};
 use futures::{prelude::*, channel::mpsc};
-use log::{warn, error, info};
+use log::{warn, error, info, trace};
 use libp2p::{PeerId, Multiaddr, kad::record};
 use libp2p::core::{transport::boxed::Boxed, muxing::StreamMuxerBox};
-use libp2p::swarm::NetworkBehaviour;
+use libp2p::swarm::{NetworkBehaviour, SwarmEvent};
 use parking_lot::Mutex;
 use sc_peerset::PeersetHandle;
 use sp_runtime::{traits::{Block as BlockT, NumberFor}, ConsensusEngineId};
@@ -774,23 +774,32 @@ impl<B: BlockT + 'static, S: NetworkSpecialization<B>, H: ExHashT> Future for Ne
 
 		loop {
 			// Process the next action coming from the network.
-			let poll_value = this.network_service.poll_next_unpin(cx);
+			let next_event = this.network_service.next_event();
+			futures::pin_mut!(next_event);
+			let poll_value = next_event.poll_unpin(cx);
 
 			match poll_value {
 				Poll::Pending => break,
-				Poll::Ready(Some(BehaviourOut::BlockImport(origin, blocks))) =>
+				Poll::Ready(SwarmEvent::Behaviour(BehaviourOut::BlockImport(origin, blocks))) =>
 					this.import_queue.import_blocks(origin, blocks),
-				Poll::Ready(Some(BehaviourOut::JustificationImport(origin, hash, nb, justification))) =>
+				Poll::Ready(SwarmEvent::Behaviour(BehaviourOut::JustificationImport(origin, hash, nb, justification))) =>
 					this.import_queue.import_justification(origin, hash, nb, justification),
-				Poll::Ready(Some(BehaviourOut::FinalityProofImport(origin, hash, nb, proof))) =>
+				Poll::Ready(SwarmEvent::Behaviour(BehaviourOut::FinalityProofImport(origin, hash, nb, proof))) =>
 					this.import_queue.import_finality_proof(origin, hash, nb, proof),
-				Poll::Ready(Some(BehaviourOut::Event(ev))) => {
-					this.event_streams.retain(|sender| sender.unbounded_send(ev.clone()).is_ok());
-				},
-				Poll::Ready(None) => {
-					error!(target: "sync", "Network events stream has returned None");
-					break;
-				},
+				Poll::Ready(SwarmEvent::Behaviour(BehaviourOut::Event(ev))) =>
+					this.event_streams.retain(|sender| sender.unbounded_send(ev.clone()).is_ok()),
+				Poll::Ready(SwarmEvent::Connected(peer_id)) =>
+					trace!(target: "sub-libp2p", "Libp2p => Connected({:?})", peer_id),
+				Poll::Ready(SwarmEvent::Disconnected(peer_id)) =>
+					trace!(target: "sub-libp2p", "Libp2p => Disconnected({:?})", peer_id),
+				Poll::Ready(SwarmEvent::NewListenAddr(addr)) =>
+					trace!(target: "sub-libp2p", "Libp2p => NewListenAddr({})", addr),
+				Poll::Ready(SwarmEvent::ExpiredListenAddr(addr)) =>
+					trace!(target: "sub-libp2p", "Libp2p => ExpiredListenAddr({})", addr),
+				Poll::Ready(SwarmEvent::UnreachableAddr { peer_id, address, error }) =>
+					trace!(target: "sub-libp2p", "Libp2p => Failed to reach {:?} through {:?}: {}", peer_id, address, error),
+				Poll::Ready(SwarmEvent::StartConnect(peer_id)) =>
+					trace!(target: "sub-libp2p", "Libp2p => StartConnect({:?})", peer_id),
 			};
 		}
 
diff --git a/client/network/test/Cargo.toml b/client/network/test/Cargo.toml
index 381276ecfa5bd..036607df921ba 100644
--- a/client/network/test/Cargo.toml
+++ b/client/network/test/Cargo.toml
@@ -1,7 +1,7 @@
 [package]
 description = "Integration tests for Substrate network protocol"
 name = "sc-network-test"
-version = "2.0.0"
+version = "0.8.0"
 license = "GPL-3.0"
 authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2018"
@@ -16,12 +16,12 @@ futures-timer = "0.4.0"
 rand = "0.7.2"
 libp2p = { version = "0.14.0-alpha.1", default-features = false, features = ["libp2p-websocket"] }
 sp-consensus = { version = "0.8", path = "../../../primitives/consensus/common" }
-sc-client = { version = "2.0.0", path = "../../" }
+sc-client = { version = "0.8", path = "../../" }
 sc-client-api = { version = "2.0.0", path = "../../api" }
 sp-blockchain = { version = "2.0.0", path = "../../../primitives/blockchain" }
 sp-runtime = { version = "2.0.0", path = "../../../primitives/runtime" }
 sp-core = { version = "2.0.0", path = "../../../primitives/core" }
-sc-block-builder = { version = "2.0.0", path = "../../block-builder" }
+sc-block-builder = { version = "0.8", path = "../../block-builder" }
 sp-consensus-babe = { version = "0.8", path = "../../../primitives/consensus/babe" }
 env_logger = "0.7.0"
 substrate-test-runtime-client = { version = "2.0.0", path = "../../../test-utils/runtime/client" }
diff --git a/client/network/test/src/sync.rs b/client/network/test/src/sync.rs
index d738eb3d6c3ed..2140de0973449 100644
--- a/client/network/test/src/sync.rs
+++ b/client/network/test/src/sync.rs
@@ -80,7 +80,7 @@ fn sync_cycle_from_offline_to_syncing_to_offline() {
 			}
 			if peer < 2 {
 				// Major syncing.
-				if !net.peer(peer).is_major_syncing() {
+				if net.peer(peer).blocks_count() < 100 && !net.peer(peer).is_major_syncing() {
 					return Ok(Async::NotReady)
 				}
 			}
diff --git a/client/offchain/Cargo.toml b/client/offchain/Cargo.toml
index 8048d10dc34fc..3ef98f1ab9004 100644
--- a/client/offchain/Cargo.toml
+++ b/client/offchain/Cargo.toml
@@ -31,7 +31,7 @@ hyper = "0.12.35"
 hyper-rustls = "0.17.1"
 
 [dev-dependencies]
-sc-client-db = { version = "2.0.0", default-features = true, path = "../db/" }
+sc-client-db = { version = "0.8", default-features = true, path = "../db/" }
 env_logger = "0.7.0"
 substrate-test-runtime-client = { version = "2.0.0", path = "../../test-utils/runtime/client" }
 tokio = "0.1.22"
diff --git a/client/offchain/src/lib.rs b/client/offchain/src/lib.rs
index e25072d42d603..78760fb011c1c 100644
--- a/client/offchain/src/lib.rs
+++ b/client/offchain/src/lib.rs
@@ -101,13 +101,14 @@ impl<Client, Storage, Block> OffchainWorkers<
 		let has_api_v1 = runtime.has_api_with::<dyn OffchainWorkerApi<Block, Error = ()>, _>(
 			&at, |v| v == 1
 		);
-		let has_api_v2 = runtime.has_api::<dyn OffchainWorkerApi<Block, Error = ()>>(&at);
+		let has_api_v2 = runtime.has_api_with::<dyn OffchainWorkerApi<Block, Error = ()>, _>(
+			&at, |v| v == 2
+		);
 		let version = match (has_api_v1, has_api_v2) {
 			(_, Ok(true)) => 2,
 			(Ok(true), _) => 1,
 			_ => 0,
 		};
-
 		debug!("Checking offchain workers at {:?}: version:{}", at, version);
 		if version > 0 {
 			let (api, runner) = api::AsyncApi::new(
@@ -139,6 +140,8 @@ impl<Client, Storage, Block> OffchainWorkers<
 			});
 			futures::future::Either::Left(runner.process())
 		} else {
+			let help = "Consider turning off offchain workers if they are not part of your runtime.";
+			log::error!("Unsupported Offchain Worker API version: {}. {}", version, help);
 			futures::future::Either::Right(futures::future::ready(()))
 		}
 	}
diff --git a/client/rpc-api/Cargo.toml b/client/rpc-api/Cargo.toml
index 2c7a2ee071d7f..7f1a12f80e80d 100644
--- a/client/rpc-api/Cargo.toml
+++ b/client/rpc-api/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "sc-rpc-api"
-version = "2.0.0"
+version = "0.8.0"
 authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2018"
 
diff --git a/client/rpc/Cargo.toml b/client/rpc/Cargo.toml
index f4a42d169a6dc..6530bff4ed652 100644
--- a/client/rpc/Cargo.toml
+++ b/client/rpc/Cargo.toml
@@ -5,9 +5,9 @@ authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2018"
 
 [dependencies]
-sc-rpc-api = { version = "2.0.0", path = "../rpc-api" }
+sc-rpc-api = { version = "0.8", path = "../rpc-api" }
 sc-client-api = { version = "2.0.0", path = "../api" }
-sc-client = { version = "2.0.0", path = "../" }
+sc-client = { version = "0.8", path = "../" }
 sp-api = { version = "2.0.0", path = "../../primitives/api" }
 codec = { package = "parity-scale-codec", version = "1.0.0" }
 futures = { version = "0.3.1", features = ["compat"] }
@@ -20,8 +20,8 @@ serde_json = "1.0.41"
 sp-session = { version = "2.0.0", path = "../../primitives/session" }
 sp-runtime = { version = "2.0.0", path = "../../primitives/runtime" }
 sp-rpc = { version = "2.0.0", path = "../../primitives/rpc" }
-sp-state-machine = { version = "2.0.0", path = "../../primitives/state-machine" }
-sc-executor = { version = "2.0.0", path = "../executor" }
+sp-state-machine = { version = "0.8", path = "../../primitives/state-machine" }
+sc-executor = { version = "0.8", path = "../executor" }
 sc-keystore = { version = "2.0.0", path = "../keystore" }
 sp-transaction-pool = { version = "2.0.0", path = "../../primitives/transaction-pool" }
 sp-blockchain = { version = "2.0.0", path = "../../primitives/blockchain" }
diff --git a/client/rpc/src/state/state_light.rs b/client/rpc/src/state/state_light.rs
index abf4631bb82eb..482eb0723ff80 100644
--- a/client/rpc/src/state/state_light.rs
+++ b/client/rpc/src/state/state_light.rs
@@ -325,8 +325,8 @@ impl<Block, F, B, E, RA> StateBackend<B, E, Block, RA> for LightState<Block, F,
 		keys: Option<Vec<StorageKey>>
 	) {
 		let keys = match keys {
-			Some(keys) => keys,
-			None => {
+			Some(keys) if !keys.is_empty() => keys,
+			_ => {
 				warn!("Cannot subscribe to all keys on light client. Subscription rejected.");
 				return;
 			}
diff --git a/client/rpc/src/state/tests.rs b/client/rpc/src/state/tests.rs
index 5951ee86a93ce..a0ab11e977204 100644
--- a/client/rpc/src/state/tests.rs
+++ b/client/rpc/src/state/tests.rs
@@ -21,7 +21,7 @@ use self::error::Error;
 use std::sync::Arc;
 use assert_matches::assert_matches;
 use futures01::stream::Stream;
-use sp_core::storage::{well_known_keys, ChildInfo};
+use sp_core::{storage::{well_known_keys, ChildInfo}, ChangesTrieConfiguration};
 use sp_core::hash::H256;
 use sp_io::hashing::blake2_256;
 use substrate_test_runtime_client::{
@@ -378,7 +378,9 @@ fn should_query_storage() {
 	}
 
 	run_tests(Arc::new(substrate_test_runtime_client::new()));
-	run_tests(Arc::new(TestClientBuilder::new().set_support_changes_trie(true).build()));
+	run_tests(Arc::new(TestClientBuilder::new()
+		.changes_trie_config(Some(ChangesTrieConfiguration::new(4, 2)))
+		.build()));
 }
 
 #[test]
@@ -399,7 +401,7 @@ fn should_return_runtime_version() {
 	let api = new_full(client.clone(), Subscriptions::new(Arc::new(core.executor())));
 
 	let result = "{\"specName\":\"test\",\"implName\":\"parity-test\",\"authoringVersion\":1,\
-		\"specVersion\":1,\"implVersion\":1,\"apis\":[[\"0xdf6acb689907609b\",2],\
+		\"specVersion\":1,\"implVersion\":2,\"apis\":[[\"0xdf6acb689907609b\",2],\
 		[\"0x37e397fc7c91f5e4\",1],[\"0xd2bc9897eed08f15\",1],[\"0x40fe3ad401f8959a\",4],\
 		[\"0xc6e9a76309f39b09\",1],[\"0xdd718d5cc53262d4\",1],[\"0xcbca25e39f142387\",1],\
 		[\"0xf78b278be53f454c\",2],[\"0xab3c0572291feb8b\",1],[\"0xbc9d89904f5b923f\",1]]}";
diff --git a/client/service/Cargo.toml b/client/service/Cargo.toml
index 42f0a73dfbfa2..9946377693110 100644
--- a/client/service/Cargo.toml
+++ b/client/service/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "sc-service"
-version = "2.0.0"
+version = "0.8.0"
 authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2018"
 
@@ -15,14 +15,14 @@ wasmtime = [
 
 [dependencies]
 derive_more = "0.99.2"
-futures = "0.1.29"
-futures03 = { package = "futures", version = "0.3.1", features = ["compat"] }
+futures01 = { package = "futures", version = "0.1.29" }
+futures = "0.3.1"
 parking_lot = "0.9.0"
 lazy_static = "1.4.0"
 log = "0.4.8"
 slog = { version = "2.5.2", features = ["nested-values"] }
 tokio-executor = "0.1.8"
-tokio-timer = "0.2.11"
+futures-timer = "2"
 exit-future = "0.2.0"
 serde = "1.0.101"
 serde_json = "1.0.41"
@@ -39,11 +39,11 @@ sp-consensus = { version = "0.8", path = "../../primitives/consensus/common" }
 sc-network = { version = "0.8", path = "../network" }
 sc-chain-spec = { version = "2.0.0", path = "../chain-spec" }
 sc-client-api = { version = "2.0.0", path = "../api" }
-sc-client = { version = "2.0.0", path = "../" }
+sc-client = { version = "0.8", path = "../" }
 sp-api = { version = "2.0.0", path = "../../primitives/api" }
-sc-client-db = { version = "2.0.0", path = "../db" }
+sc-client-db = { version = "0.8", path = "../db" }
 codec = { package = "parity-scale-codec", version = "1.0.0" }
-sc-executor = { version = "2.0.0", path = "../executor" }
+sc-executor = { version = "0.8", path = "../executor" }
 sc-transaction-pool = { version = "2.0.0", path = "../transaction-pool" }
 sp-transaction-pool = { version = "2.0.0", path = "../../primitives/transaction-pool" }
 sc-rpc-server = { version = "2.0.0", path = "../rpc-servers" }
@@ -51,13 +51,13 @@ sc-rpc = { version = "2.0.0", path = "../rpc" }
 sc-telemetry = { version = "2.0.0", path = "../telemetry" }
 sc-offchain = { version = "2.0.0", path = "../offchain" }
 parity-multiaddr = { package = "parity-multiaddr", version = "0.5.0" }
-prometheus-endpoint = { path = "../../utils/prometheus" }
+prometheus-exporter = { path = "../../utils/prometheus" }
 sc-tracing = { version = "2.0.0", path = "../tracing" }
 tracing = "0.1.10"
 
 [dev-dependencies]
 substrate-test-runtime-client = { version = "2.0.0", path = "../../test-utils/runtime/client" }
 sp-consensus-babe = { version = "0.8", path = "../../primitives/consensus/babe" }
-grandpa = { version = "2.0.0", package = "sc-finality-grandpa", path = "../finality-grandpa" }
+grandpa = { version = "0.8", package = "sc-finality-grandpa", path = "../finality-grandpa" }
 grandpa-primitives = { version = "2.0.0", package = "sp-finality-grandpa", path = "../../primitives/finality-grandpa" }
-tokio = "0.1"
+tokio = { version = "0.2", features = ["rt-core"] }
diff --git a/client/service/src/builder.rs b/client/service/src/builder.rs
index 2e4b1ee6af48c..85d4091eed02b 100644
--- a/client/service/src/builder.rs
+++ b/client/service/src/builder.rs
@@ -27,12 +27,10 @@ use sc_client_api::{
 use sc_client::Client;
 use sc_chain_spec::{RuntimeGenesis, Extension};
 use sp_consensus::import_queue::ImportQueue;
-use futures::{prelude::*, sync::mpsc};
-use futures03::{
-	compat::Compat,
-	FutureExt as _, TryFutureExt as _,
-	StreamExt as _, TryStreamExt as _,
-	future::{select, Either}
+use futures::{
+	Future, FutureExt, StreamExt,
+	channel::mpsc,
+	future::{select, ready}
 };
 use sc_keystore::{Store as Keystore};
 use log::{info, warn, error};
@@ -41,52 +39,56 @@ use sc_network::{config::BoxFinalityProofRequestBuilder, specialization::Network
 use parking_lot::{Mutex, RwLock};
 use sp_runtime::generic::BlockId;
 use sp_runtime::traits::{
-	Block as BlockT, NumberFor, SaturatedConversion, HasherFor,
+	Block as BlockT, NumberFor, SaturatedConversion, HasherFor, UniqueSaturatedInto,
 };
 use sp_api::ProvideRuntimeApi;
 use sc_executor::{NativeExecutor, NativeExecutionDispatch};
 use std::{
 	io::{Read, Write, Seek},
-	marker::PhantomData, sync::Arc, time::SystemTime
+	marker::PhantomData, sync::Arc, time::SystemTime, pin::Pin
 };
 use sysinfo::{get_current_pid, ProcessExt, System, SystemExt};
 use sc_telemetry::{telemetry, SUBSTRATE_INFO};
 use sp_transaction_pool::{TransactionPool, TransactionPoolMaintainer};
 use sp_blockchain;
-use prometheus_endpoint::{create_gauge, Gauge, U64, F64};
+use prometheus_exporter::{create_gauge, Gauge, U64, F64, Registry};
 
-prometheus_endpoint::lazy_static! {
+prometheus_exporter::lazy_static! {
 	pub static ref FINALITY_HEIGHT: Gauge<U64> = create_gauge(
-		"consensus_finality_block_height_number",
-		"block is finality HEIGHT"
+		"finality_block_height_number",
+		"Height of the highest finalized block"
 	);
 	pub static ref BEST_HEIGHT: Gauge<U64> = create_gauge(
-		"consensus_best_block_height_number",
-		"block is best HEIGHT"
+		"best_block_height_number",
+		"Height of the highest block"
 	);
-	pub static ref P2P_PEERS_NUM: Gauge<U64> = create_gauge(
-		"p2p_peers_number",
-		"network gosip peers number"
+	pub static ref PEERS_NUM: Gauge<U64> = create_gauge(
+		"peers_count",
+		"Number of network gossip peers"
 	);
 	pub static ref TX_COUNT: Gauge<U64> = create_gauge(
-		"consensus_num_txs",
+		"transaction_count",
 		"Number of transactions"
 	);
 	pub static ref NODE_MEMORY: Gauge<U64> = create_gauge(
-		"consensus_node_memory",
-		"node memory"
+		"memory_usage",
+		"Node memory usage"
 	);
 	pub static ref NODE_CPU: Gauge<F64> = create_gauge(
-		"consensus_node_cpu",
-		"node cpu"
+		"cpu_usage",
+		"Node CPU usage"
 	);
-	pub static ref P2P_NODE_DOWNLOAD: Gauge<U64> = create_gauge(
-		"p2p_peers_receive_byte_per_sec",
-		"p2p_node_download_per_sec_byte"
+	pub static ref NODE_DOWNLOAD: Gauge<U64> = create_gauge(
+		"receive_byte_per_sec",
+		"Received bytes per second"
 	);
-	pub static ref P2P_NODE_UPLOAD: Gauge<U64> = create_gauge(
-		"p2p_peers_send_byte_per_sec",
-		"p2p_node_upload_per_sec_byte"
+	pub static ref NODE_UPLOAD: Gauge<U64> = create_gauge(
+		"sent_byte_per_sec",
+		"Sent bytes per second"
+	);
+	pub static ref SYNC_TARGET: Gauge<U64> = create_gauge(
+		"sync_target_number",
+		"Block sync target number"
 	);
 }
 /// Aggregator for the components required to build a service.
@@ -124,6 +126,7 @@ pub struct ServiceBuilder<TBl, TRtApi, TCfg, TGen, TCSExt, TCl, TFchr, TSc, TImp
 	rpc_extensions: TRpc,
 	remote_backend: Option<Arc<dyn RemoteBlockchain<TBl>>>,
 	marker: PhantomData<(TBl, TRtApi)>,
+	prometheus_registry: Option<Registry>
 }
 
 /// Full client type.
@@ -183,7 +186,7 @@ pub fn new_full_client<TBl, TRtApi, TExecDisp, TCfg, TGen, TCSExt>(
 	config: &Configuration<TCfg, TGen, TCSExt>,
 ) -> Result<TFullClient<TBl, TRtApi, TExecDisp>, Error> where
 	TBl: BlockT,
-	TExecDisp: NativeExecutionDispatch,
+	TExecDisp: NativeExecutionDispatch + 'static,
 	TGen: sp_runtime::BuildStorage + serde::Serialize + for<'de> serde::Deserialize<'de>,
 	TCSExt: Extension,
 {
@@ -194,7 +197,7 @@ fn new_full_parts<TBl, TRtApi, TExecDisp, TCfg, TGen, TCSExt>(
 	config: &Configuration<TCfg, TGen, TCSExt>,
 ) -> Result<TFullParts<TBl, TRtApi, TExecDisp>,	Error> where
 	TBl: BlockT,
-	TExecDisp: NativeExecutionDispatch,
+	TExecDisp: NativeExecutionDispatch + 'static,
 	TGen: sp_runtime::BuildStorage + serde::Serialize + for<'de> serde::Deserialize<'de>,
 	TCSExt: Extension,
 {
@@ -262,7 +265,7 @@ fn new_full_parts<TBl, TRtApi, TExecDisp, TCfg, TGen, TCSExt>(
 impl<TCfg, TGen, TCSExt> ServiceBuilder<(), (), TCfg, TGen, TCSExt, (), (), (), (), (), (), (), (), (), ()>
 where TGen: RuntimeGenesis, TCSExt: Extension {
 	/// Start the service builder with a configuration.
-	pub fn new_full<TBl: BlockT, TRtApi, TExecDisp: NativeExecutionDispatch>(
+	pub fn new_full<TBl: BlockT, TRtApi, TExecDisp: NativeExecutionDispatch + 'static>(
 		config: Configuration<TCfg, TGen, TCSExt>
 	) -> Result<ServiceBuilder<
 		TBl,
@@ -300,6 +303,7 @@ where TGen: RuntimeGenesis, TCSExt: Extension {
 			rpc_extensions: Default::default(),
 			remote_backend: None,
 			marker: PhantomData,
+			prometheus_registry: None,
 		})
 	}
 
@@ -386,6 +390,7 @@ where TGen: RuntimeGenesis, TCSExt: Extension {
 			rpc_extensions: Default::default(),
 			remote_backend: Some(remote_blockchain),
 			marker: PhantomData,
+			prometheus_registry: None,
 		})
 	}
 }
@@ -434,6 +439,7 @@ impl<TBl, TRtApi, TCfg, TGen, TCSExt, TCl, TFchr, TSc, TImpQu, TFprb, TFpp, TNet
 			rpc_extensions: self.rpc_extensions,
 			remote_backend: self.remote_backend,
 			marker: self.marker,
+			prometheus_registry: self.prometheus_registry,
 		})
 	}
 
@@ -476,6 +482,7 @@ impl<TBl, TRtApi, TCfg, TGen, TCSExt, TCl, TFchr, TSc, TImpQu, TFprb, TFpp, TNet
 			rpc_extensions: self.rpc_extensions,
 			remote_backend: self.remote_backend,
 			marker: self.marker,
+			prometheus_registry: self.prometheus_registry,
 		})
 	}
 
@@ -502,6 +509,7 @@ impl<TBl, TRtApi, TCfg, TGen, TCSExt, TCl, TFchr, TSc, TImpQu, TFprb, TFpp, TNet
 			rpc_extensions: self.rpc_extensions,
 			remote_backend: self.remote_backend,
 			marker: self.marker,
+			prometheus_registry: self.prometheus_registry,
 		})
 	}
 
@@ -543,6 +551,7 @@ impl<TBl, TRtApi, TCfg, TGen, TCSExt, TCl, TFchr, TSc, TImpQu, TFprb, TFpp, TNet
 			rpc_extensions: self.rpc_extensions,
 			remote_backend: self.remote_backend,
 			marker: self.marker,
+			prometheus_registry: self.prometheus_registry,
 		})
 	}
 
@@ -608,6 +617,7 @@ impl<TBl, TRtApi, TCfg, TGen, TCSExt, TCl, TFchr, TSc, TImpQu, TFprb, TFpp, TNet
 			rpc_extensions: self.rpc_extensions,
 			remote_backend: self.remote_backend,
 			marker: self.marker,
+			prometheus_registry: self.prometheus_registry,
 		})
 	}
 
@@ -663,6 +673,7 @@ impl<TBl, TRtApi, TCfg, TGen, TCSExt, TCl, TFchr, TSc, TImpQu, TFprb, TFpp, TNet
 			rpc_extensions: self.rpc_extensions,
 			remote_backend: self.remote_backend,
 			marker: self.marker,
+			prometheus_registry: self.prometheus_registry,
 		})
 	}
 
@@ -702,8 +713,30 @@ impl<TBl, TRtApi, TCfg, TGen, TCSExt, TCl, TFchr, TSc, TImpQu, TFprb, TFpp, TNet
 			rpc_extensions,
 			remote_backend: self.remote_backend,
 			marker: self.marker,
+			prometheus_registry: self.prometheus_registry,
 		})
 	}
+
+	/// Use an existing prometheus `Registry` to record metrics into.
+	pub fn with_prometheus_registry(self, registry: Registry) -> Self {
+		Self {
+			config: self.config,
+			client: self.client,
+			backend: self.backend,
+			keystore: self.keystore,
+			fetcher: self.fetcher,
+			select_chain: self.select_chain,
+			import_queue: self.import_queue,
+			finality_proof_request_builder: self.finality_proof_request_builder,
+			finality_proof_provider: self.finality_proof_provider,
+			network_protocol: self.network_protocol,
+			transaction_pool: self.transaction_pool,
+			rpc_extensions: self.rpc_extensions,
+			remote_backend: self.remote_backend,
+			marker: self.marker,
+			prometheus_registry: Some(registry),
+		}
+	}
 }
 
 /// Implemented on `ServiceBuilder`. Allows running block commands, such as import/export/validate
@@ -716,7 +749,7 @@ pub trait ServiceBuilderCommand {
 		self,
 		input: impl Read + Seek + Send + 'static,
 		force: bool,
-	) -> Box<dyn Future<Item = (), Error = Error> + Send>;
+	) -> Pin<Box<dyn Future<Output = Result<(), Error>> + Send>>;
 
 	/// Performs the blocks export.
 	fn export_blocks(
@@ -725,7 +758,7 @@ pub trait ServiceBuilderCommand {
 		from: NumberFor<Self::Block>,
 		to: Option<NumberFor<Self::Block>>,
 		json: bool
-	) -> Box<dyn Future<Item = (), Error = Error>>;
+	) -> Pin<Box<dyn Future<Output = Result<(), Error>>>>;
 
 	/// Performs a revert of `blocks` blocks.
 	fn revert_chain(
@@ -737,7 +770,7 @@ pub trait ServiceBuilderCommand {
 	fn check_block(
 		self,
 		block: BlockId<Self::Block>
-	) -> Box<dyn Future<Item = (), Error = Error> + Send>;
+	) -> Pin<Box<dyn Future<Output = Result<(), Error>> + Send>>;
 }
 
 impl<TBl, TRtApi, TCfg, TGen, TCSExt, TBackend, TExec, TSc, TImpQu, TNetP, TExPool, TRpc>
@@ -817,6 +850,7 @@ ServiceBuilder<
 			transaction_pool,
 			rpc_extensions,
 			remote_backend,
+			prometheus_registry,
 		} = self;
 
 		sp_session::generate_initial_session_keys(
@@ -829,7 +863,7 @@ ServiceBuilder<
 
 		// List of asynchronous tasks to spawn. We collect them, then spawn them all at once.
 		let (to_spawn_tx, to_spawn_rx) =
-			mpsc::unbounded::<Box<dyn Future<Item = (), Error = ()> + Send>>();
+			mpsc::unbounded::<Pin<Box<dyn Future<Output = ()> + Send>>>();
 
 		// A side-channel for essential tasks to communicate shutdown.
 		let (essential_failed_tx, essential_failed_rx) = mpsc::unbounded();
@@ -913,7 +947,6 @@ ServiceBuilder<
 			let is_validator = config.roles.is_authority();
 
 			let events = client.import_notification_stream()
-				.map(|v| Ok::<_, ()>(v)).compat()
 				.for_each(move |notification| {
 					let txpool = txpool.upgrade();
 
@@ -921,8 +954,8 @@ ServiceBuilder<
 						let future = txpool.maintain(
 							&BlockId::hash(notification.hash),
 							&notification.retracted,
-						).map(|_| Ok(())).compat();
-						let _ = to_spawn_tx_.unbounded_send(Box::new(future));
+						);
+						let _ = to_spawn_tx_.unbounded_send(Box::pin(future));
 					}
 
 					let offchain = offchain.as_ref().and_then(|o| o.upgrade());
@@ -931,15 +964,13 @@ ServiceBuilder<
 							&notification.header,
 							network_state_info.clone(),
 							is_validator
-						).map(|()| Ok(()));
-						let _ = to_spawn_tx_.unbounded_send(Box::new(Compat::new(future)));
+						);
+						let _ = to_spawn_tx_.unbounded_send(Box::pin(future));
 					}
 
-					Ok(())
-				})
-				.select(exit.clone().map(Ok).compat())
-				.then(|_| Ok(()));
-			let _ = to_spawn_tx.unbounded_send(Box::new(events));
+					ready(())
+				});
+			let _ = to_spawn_tx.unbounded_send(Box::pin(select(events, exit.clone()).map(drop)));
 		}
 
 		{
@@ -947,7 +978,6 @@ ServiceBuilder<
 			let network = Arc::downgrade(&network);
 			let transaction_pool_ = transaction_pool.clone();
 			let events = transaction_pool.import_notification_stream()
-				.map(|v| Ok::<_, ()>(v)).compat()
 				.for_each(move |_| {
 					if let Some(network) = network.upgrade() {
 						network.trigger_repropagate();
@@ -957,12 +987,10 @@ ServiceBuilder<
 						"ready" => status.ready,
 						"future" => status.future
 					);
-					Ok(())
-				})
-				.select(exit.clone().map(Ok).compat())
-				.then(|_| Ok(()));
+					ready(())
+				});
 
-			let _ = to_spawn_tx.unbounded_send(Box::new(events));
+			let _ = to_spawn_tx.unbounded_send(Box::pin(select(events, exit.clone()).map(drop)));
 		}
 
 		// Periodically notify the telemetry.
@@ -981,6 +1009,8 @@ ServiceBuilder<
 			let finalized_number: u64 = info.chain.finalized_number.saturated_into::<u64>();
 			let bandwidth_download = net_status.average_download_per_sec;
 			let bandwidth_upload = net_status.average_upload_per_sec;
+			let best_seen_block = net_status.best_seen_block
+				.map(|num: NumberFor<TBl>| num.unique_saturated_into() as u64);
 
 			// get cpu usage and memory usage of this process
 			let (cpu_usage, memory) = if let Some(self_pid) = self_pid {
@@ -1014,12 +1044,16 @@ ServiceBuilder<
 			TX_COUNT.set(txpool_status.ready as u64);
 			FINALITY_HEIGHT.set(finalized_number);
 			BEST_HEIGHT.set(best_number);
-			P2P_PEERS_NUM.set(num_peers as u64);
-			P2P_NODE_DOWNLOAD.set(net_status.average_download_per_sec);
-			P2P_NODE_UPLOAD.set(net_status.average_upload_per_sec);
-			Ok(())
-		}).select(exit.clone().map(Ok).compat()).then(|_| Ok(()));
-		let _ = to_spawn_tx.unbounded_send(Box::new(tel_task));
+			PEERS_NUM.set(num_peers as u64);
+			NODE_DOWNLOAD.set(net_status.average_download_per_sec);
+			NODE_UPLOAD.set(net_status.average_upload_per_sec);
+			if let Some(best_seen_block) = best_seen_block {
+				SYNC_TARGET.set(best_seen_block);
+			}
+
+			ready(())
+		});
+		let _ = to_spawn_tx.unbounded_send(Box::pin(select(tel_task, exit.clone()).map(drop)));
 
 		// Periodically send the network state to the telemetry.
 		let (netstat_tx, netstat_rx) = mpsc::unbounded::<(NetworkStatus<_>, NetworkState)>();
@@ -1030,12 +1064,12 @@ ServiceBuilder<
 				"system.network_state";
 				"state" => network_state,
 			);
-			Ok(())
-		}).select(exit.clone().map(Ok).compat()).then(|_| Ok(()));
-		let _ = to_spawn_tx.unbounded_send(Box::new(tel_task_2));
+			ready(())
+		});
+		let _ = to_spawn_tx.unbounded_send(Box::pin(select(tel_task_2, exit.clone()).map(drop)));
 
 		// RPC
-		let (system_rpc_tx, system_rpc_rx) = futures03::channel::mpsc::unbounded();
+		let (system_rpc_tx, system_rpc_rx) = mpsc::unbounded();
 		let gen_handler = || {
 			use sc_rpc::{chain, state, author, system};
 
@@ -1095,17 +1129,14 @@ ServiceBuilder<
 		let rpc = start_rpc_servers(&config, gen_handler)?;
 
 
-		let _ = to_spawn_tx.unbounded_send(Box::new(build_network_future(
+		let _ = to_spawn_tx.unbounded_send(Box::pin(select(build_network_future(
 			config.roles,
 			network_mut,
 			client.clone(),
 			network_status_sinks.clone(),
 			system_rpc_rx,
 			has_bootnodes,
-		)
-			.map_err(|_| ())
-			.select(exit.clone().map(Ok).compat())
-			.then(|_| Ok(()))));
+		), exit.clone()).map(drop)));
 
 		let telemetry_connection_sinks: Arc<Mutex<Vec<mpsc::UnboundedSender<()>>>> = Default::default();
 
@@ -1126,8 +1157,6 @@ ServiceBuilder<
 				.map(|dur| dur.as_millis())
 				.unwrap_or(0);
 			let future = telemetry.clone()
-				.map(|ev| Ok::<_, ()>(ev))
-				.compat()
 				.for_each(move |event| {
 					// Safe-guard in case we add more events in the future.
 					let sc_telemetry::TelemetryEvent::Connected = event;
@@ -1146,25 +1175,36 @@ ServiceBuilder<
 					telemetry_connection_sinks_.lock().retain(|sink| {
 						sink.unbounded_send(()).is_ok()
 					});
-					Ok(())
+					ready(())
 				});
-			let _ = to_spawn_tx.unbounded_send(Box::new(future
-				.select(exit.clone().map(Ok).compat())
-				.then(|_| Ok(()))));
+			let _ = to_spawn_tx.unbounded_send(Box::pin(select(
+				future, exit.clone()
+			).map(drop)));
 			telemetry
 		});
-		// Prometheus endpoint
+		// Prometheus exporter
 		if let Some(port) = config.prometheus_port {
+			let registry = match prometheus_registry {
+				Some(registry) => registry,
+				None => Registry::new_custom(Some("substrate".into()), None)?
+			};
+
+			registry.register(Box::new(NODE_MEMORY.clone()))?;
+			registry.register(Box::new(NODE_CPU.clone()))?;
+			registry.register(Box::new(TX_COUNT.clone()))?;
+			registry.register(Box::new(FINALITY_HEIGHT.clone()))?;
+			registry.register(Box::new(BEST_HEIGHT.clone()))?;
+			registry.register(Box::new(PEERS_NUM.clone()))?;
+			registry.register(Box::new(NODE_DOWNLOAD.clone()))?;
+			registry.register(Box::new(NODE_UPLOAD.clone()))?;
+
 			let future = select(
-				prometheus_endpoint::init_prometheus(port).boxed(),
+				prometheus_exporter::init_prometheus(port, registry).boxed(),
 				exit.clone()
-			).map(|either| match either {
-				Either::Left((result, _)) => result.map_err(|_| ()),
-				Either::Right(_) => Ok(())
-			}).compat();
+			).map(drop);
 
-			let _ = to_spawn_tx.unbounded_send(Box::new(future));
-		}
+			let _ = to_spawn_tx.unbounded_send(Box::pin(future));
+    	}
 
 		// Instrumentation
 		if let Some(tracing_targets) = config.tracing_targets.as_ref() {
diff --git a/client/service/src/chain_ops.rs b/client/service/src/chain_ops.rs
index 0b86fb366f0b6..0c2fe79718a72 100644
--- a/client/service/src/chain_ops.rs
+++ b/client/service/src/chain_ops.rs
@@ -22,9 +22,6 @@ use crate::error::Error;
 use sc_chain_spec::{ChainSpec, RuntimeGenesis, Extension};
 use log::{warn, info};
 use futures::{future, prelude::*};
-use futures03::{
-	TryFutureExt as _,
-};
 use sp_runtime::traits::{
 	Block as BlockT, NumberFor, One, Zero, Header, SaturatedConversion
 };
@@ -34,9 +31,7 @@ use sc_client::Client;
 use sp_consensus::import_queue::{IncomingBlock, Link, BlockImportError, BlockImportResult, ImportQueue};
 use sp_consensus::BlockOrigin;
 
-use std::{
-	io::{Read, Write, Seek},
-};
+use std::{io::{Read, Write, Seek}, pin::Pin};
 
 use sc_network::message;
 
@@ -68,7 +63,7 @@ impl<
 		self,
 		input: impl Read + Seek + Send + 'static,
 		force: bool,
-	) -> Box<dyn Future<Item = (), Error = Error> + Send> {
+	) -> Pin<Box<dyn Future<Output = Result<(), Error>> + Send>> {
 		struct WaitLink {
 			imported_blocks: u64,
 			has_error: bool,
@@ -117,7 +112,7 @@ impl<
 		// queue, the `Future` re-schedules itself and returns `Poll::Pending`.
 		// This makes it possible either to interleave other operations in-between the block imports,
 		// or to stop the operation completely.
-		let import = futures03::future::poll_fn(move |cx| {
+		let import = future::poll_fn(move |cx| {
 			// Start by reading the number of blocks if not done so already.
 			let count = match count {
 				Some(c) => c,
@@ -205,7 +200,7 @@ impl<
 				return std::task::Poll::Pending;
 			}
 		});
-		Box::new(import.compat())
+		Box::pin(import)
 	}
 
 	fn export_blocks(
@@ -214,7 +209,7 @@ impl<
 		from: NumberFor<TBl>,
 		to: Option<NumberFor<TBl>>,
 		json: bool
-	) -> Box<dyn Future<Item = (), Error = Error>> {
+	) -> Pin<Box<dyn Future<Output = Result<(), Error>>>> {
 		let client = self.client;
 		let mut block = from;
 
@@ -233,7 +228,7 @@ impl<
 		// `Poll::Pending`.
 		// This makes it possible either to interleave other operations in-between the block exports,
 		// or to stop the operation completely.
-		let export = futures03::future::poll_fn(move |cx| {
+		let export = future::poll_fn(move |cx| {
 			if last < block {
 				return std::task::Poll::Ready(Err("Invalid block range specified".into()));
 			}
@@ -274,7 +269,7 @@ impl<
 			std::task::Poll::Pending
 		});
 
-		Box::new(export.compat())
+		Box::pin(export)
 	}
 
 	fn revert_chain(
@@ -295,7 +290,7 @@ impl<
 	fn check_block(
 		self,
 		block_id: BlockId<TBl>
-	) -> Box<dyn Future<Item = (), Error = Error> + Send> {
+	) -> Pin<Box<dyn Future<Output = Result<(), Error>> + Send>> {
 		match self.client.block(&block_id) {
 			Ok(Some(block)) => {
 				let mut buf = Vec::new();
@@ -304,8 +299,8 @@ impl<
 				let reader = std::io::Cursor::new(buf);
 				self.import_blocks(reader, true)
 			}
-			Ok(None) => Box::new(future::err("Unknown block".into())),
-			Err(e) => Box::new(future::err(format!("Error reading block: {:?}", e).into())),
+			Ok(None) => Box::pin(future::err("Unknown block".into())),
+			Err(e) => Box::pin(future::err(format!("Error reading block: {:?}", e).into())),
 		}
 	}
 }
diff --git a/client/service/src/config.rs b/client/service/src/config.rs
index 9aa7f795ddeca..994ef2e3723b9 100644
--- a/client/service/src/config.rs
+++ b/client/service/src/config.rs
@@ -73,7 +73,7 @@ pub struct Configuration<C, G, E = NoExtension> {
 	pub rpc_ws_max_connections: Option<usize>,
 	/// CORS settings for HTTP & WS servers. `None` if all origins are allowed.
 	pub rpc_cors: Option<Vec<String>>,
-	/// Prometheus endpoint Port. `None` if disabled.
+	/// Prometheus exporter Port. `None` if disabled.
 	pub prometheus_port: Option<SocketAddr>,
 	/// Telemetry service URL. `None` if disabled.
 	pub telemetry_endpoints: Option<TelemetryEndpoints>,
diff --git a/client/service/src/error.rs b/client/service/src/error.rs
index 6516b1c62c6d6..4cbd172e4b2b3 100644
--- a/client/service/src/error.rs
+++ b/client/service/src/error.rs
@@ -50,6 +50,12 @@ impl<'a> From<&'a str> for Error {
 	}
 }
 
+impl From<prometheus_exporter::PrometheusError> for Error {
+	fn from(e: prometheus_exporter::PrometheusError) -> Self {
+		Error::Other(format!("Prometheus error: {}", e))
+	}
+}
+
 impl std::error::Error for Error {
 	fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
 		match self {
diff --git a/client/service/src/lib.rs b/client/service/src/lib.rs
index 7a3c6fc9eaab3..87327d0967583 100644
--- a/client/service/src/lib.rs
+++ b/client/service/src/lib.rs
@@ -32,15 +32,17 @@ use std::marker::PhantomData;
 use std::net::SocketAddr;
 use std::collections::HashMap;
 use std::time::{Duration, Instant};
-use futures::sync::mpsc;
+use std::task::{Poll, Context};
 use parking_lot::Mutex;
 
 use sc_client::Client;
 use exit_future::Signal;
-use futures::prelude::*;
-use futures03::{
-	future::{ready, FutureExt as _, TryFutureExt as _},
-	stream::{StreamExt as _, TryStreamExt as _},
+use futures::{
+	Future, FutureExt, Stream, StreamExt, TryFutureExt,
+	future::select, channel::mpsc,
+	compat::*,
+	sink::SinkExt,
+	task::{Spawn, SpawnExt, FutureObj, SpawnError},
 };
 use sc_network::{
 	NetworkService, NetworkState, specialization::NetworkSpecialization,
@@ -67,8 +69,6 @@ pub use sc_rpc::Metadata as RpcMetadata;
 pub use std::{ops::Deref, result::Result, sync::Arc};
 #[doc(hidden)]
 pub use sc_network::{FinalityProofProvider, OnDemand, config::BoxFinalityProofRequestBuilder};
-#[doc(hidden)]
-pub use futures::future::Executor;
 
 const DEFAULT_PROTOCOL_ID: &str = "sup";
 
@@ -92,13 +92,13 @@ pub struct Service<TBl, TCl, TSc, TNetStatus, TNet, TTxPool, TOc> {
 	/// A receiver for spawned essential-tasks concluding.
 	essential_failed_rx: mpsc::UnboundedReceiver<()>,
 	/// Sender for futures that must be spawned as background tasks.
-	to_spawn_tx: mpsc::UnboundedSender<Box<dyn Future<Item = (), Error = ()> + Send>>,
+	to_spawn_tx: mpsc::UnboundedSender<Pin<Box<dyn Future<Output = ()> + Send>>>,
 	/// Receiver for futures that must be spawned as background tasks.
-	to_spawn_rx: mpsc::UnboundedReceiver<Box<dyn Future<Item = (), Error = ()> + Send>>,
+	to_spawn_rx: mpsc::UnboundedReceiver<Pin<Box<dyn Future<Output = ()> + Send>>>,
 	/// List of futures to poll from `poll`.
 	/// If spawning a background task is not possible, we instead push the task into this `Vec`.
 	/// The elements must then be polled manually.
-	to_poll: Vec<Box<dyn Future<Item = (), Error = ()> + Send>>,
+	to_poll: Vec<Pin<Box<dyn Future<Output = ()> + Send>>>,
 	rpc_handlers: sc_rpc_server::RpcHandler<sc_rpc::Metadata>,
 	_rpc: Box<dyn std::any::Any + Send + Sync>,
 	_telemetry: Option<sc_telemetry::Telemetry>,
@@ -109,42 +109,36 @@ pub struct Service<TBl, TCl, TSc, TNetStatus, TNet, TTxPool, TOc> {
 }
 
 /// Alias for a an implementation of `futures::future::Executor`.
-pub type TaskExecutor = Arc<dyn Executor<Box<dyn Future<Item = (), Error = ()> + Send>> + Send + Sync>;
+pub type TaskExecutor = Arc<dyn Spawn + Send + Sync>;
 
 /// An handle for spawning tasks in the service.
 #[derive(Clone)]
 pub struct SpawnTaskHandle {
-	sender: mpsc::UnboundedSender<Box<dyn Future<Item = (), Error = ()> + Send>>,
+	sender: mpsc::UnboundedSender<Pin<Box<dyn Future<Output = ()> + Send>>>,
 	on_exit: exit_future::Exit,
 }
 
-impl Executor<Box<dyn Future<Item = (), Error = ()> + Send>> for SpawnTaskHandle {
-	fn execute(
-		&self,
-		future: Box<dyn Future<Item = (), Error = ()> + Send>,
-	) -> Result<(), futures::future::ExecuteError<Box<dyn Future<Item = (), Error = ()> + Send>>> {
-		let exit = self.on_exit.clone().map(Ok).compat();
-		let future = Box::new(future.select(exit).then(|_| Ok(())));
-		if let Err(err) = self.sender.unbounded_send(future) {
-			let kind = futures::future::ExecuteErrorKind::Shutdown;
-			Err(futures::future::ExecuteError::new(kind, err.into_inner()))
-		} else {
-			Ok(())
-		}
+impl Spawn for SpawnTaskHandle {
+	fn spawn_obj(&self, future: FutureObj<'static, ()>)
+	-> Result<(), SpawnError> {
+		let future = select(self.on_exit.clone(), future).map(drop);
+		self.sender.unbounded_send(Box::pin(future))
+			.map_err(|_| SpawnError::shutdown())
 	}
 }
 
-impl futures03::task::Spawn for SpawnTaskHandle {
-	fn spawn_obj(&self, future: futures03::task::FutureObj<'static, ()>)
-	-> Result<(), futures03::task::SpawnError> {
-		self.execute(Box::new(futures03::compat::Compat::new(future.unit_error())))
-			.map_err(|_| futures03::task::SpawnError::shutdown())
+type Boxed01Future01 = Box<dyn futures01::Future<Item = (), Error = ()> + Send + 'static>;
+
+impl futures01::future::Executor<Boxed01Future01> for SpawnTaskHandle {
+	fn execute(&self, future: Boxed01Future01) -> Result<(), futures01::future::ExecuteError<Boxed01Future01>>{
+		self.spawn(future.compat().map(drop));
+		Ok(())
 	}
 }
 
 /// Abstraction over a Substrate service.
-pub trait AbstractService: 'static + Future<Item = (), Error = Error> +
-	Executor<Box<dyn Future<Item = (), Error = ()> + Send>> + Send {
+pub trait AbstractService: 'static + Future<Output = Result<(), Error>> +
+	Spawn + Send + Unpin {
 	/// Type of block of this chain.
 	type Block: BlockT;
 	/// Backend storage for the client.
@@ -168,12 +162,12 @@ pub trait AbstractService: 'static + Future<Item = (), Error = Error> +
 	fn telemetry(&self) -> Option<sc_telemetry::Telemetry>;
 
 	/// Spawns a task in the background that runs the future passed as parameter.
-	fn spawn_task(&self, task: impl Future<Item = (), Error = ()> + Send + 'static);
+	fn spawn_task(&self, task: impl Future<Output = ()> + Send + Unpin + 'static);
 
 	/// Spawns a task in the background that runs the future passed as
 	/// parameter. The given task is considered essential, i.e. if it errors we
 	/// trigger a service exit.
-	fn spawn_essential_task(&self, task: impl Future<Item = (), Error = ()> + Send + 'static);
+	fn spawn_essential_task(&self, task: impl Future<Output = ()> + Send + Unpin + 'static);
 
 	/// Returns a handle for spawning tasks.
 	fn spawn_task_handle(&self) -> SpawnTaskHandle;
@@ -190,7 +184,7 @@ pub trait AbstractService: 'static + Future<Item = (), Error = Error> +
 	///
 	/// If the request subscribes you to events, the `Sender` in the `RpcSession` object is used to
 	/// send back spontaneous events.
-	fn rpc_query(&self, mem: &RpcSession, request: &str) -> Box<dyn Future<Item = Option<String>, Error = ()> + Send>;
+	fn rpc_query(&self, mem: &RpcSession, request: &str) -> Pin<Box<dyn Future<Output = Option<String>> + Send>>;
 
 	/// Get shared client instance.
 	fn client(&self) -> Arc<sc_client::Client<Self::Backend, Self::CallExecutor, Self::Block, Self::RuntimeApi>>;
@@ -216,11 +210,11 @@ impl<TBl, TBackend, TExec, TRtApi, TSc, TNetSpec, TExPool, TOc> AbstractService
 	Service<TBl, Client<TBackend, TExec, TBl, TRtApi>, TSc, NetworkStatus<TBl>,
 		NetworkService<TBl, TNetSpec, TBl::Hash>, TExPool, TOc>
 where
-	TBl: BlockT,
+	TBl: BlockT + Unpin,
 	TBackend: 'static + sc_client_api::backend::Backend<TBl>,
 	TExec: 'static + sc_client::CallExecutor<TBl> + Send + Sync + Clone,
 	TRtApi: 'static + Send + Sync,
-	TSc: sp_consensus::SelectChain<TBl> + 'static + Clone + Send,
+	TSc: sp_consensus::SelectChain<TBl> + 'static + Clone + Send + Unpin,
 	TExPool: 'static + TransactionPool<Block = TBl>
 		+ TransactionPoolMaintainer<Block = TBl>,
 	TOc: 'static + Send + Sync,
@@ -248,25 +242,22 @@ where
 		self.keystore.clone()
 	}
 
-	fn spawn_task(&self, task: impl Future<Item = (), Error = ()> + Send + 'static) {
-		let exit = self.on_exit().map(Ok).compat();
-		let task = task.select(exit).then(|_| Ok(()));
-		let _ = self.to_spawn_tx.unbounded_send(Box::new(task));
+	fn spawn_task(&self, task: impl Future<Output = ()> + Send + Unpin + 'static) {
+		let task = select(self.on_exit(), task).map(drop);
+		let _ = self.to_spawn_tx.unbounded_send(Box::pin(task));
 	}
 
-	fn spawn_essential_task(&self, task: impl Future<Item = (), Error = ()> + Send + 'static) {
-		let essential_failed = self.essential_failed_tx.clone();
+	fn spawn_essential_task(&self, task: impl Future<Output = ()> + Send + Unpin + 'static) {
+		let mut essential_failed = self.essential_failed_tx.clone();
 		let essential_task = std::panic::AssertUnwindSafe(task)
 			.catch_unwind()
-			.then(move |_| {
+			.map(move |_| {
 				error!("Essential task failed. Shutting down service.");
 				let _ = essential_failed.send(());
-				Ok(())
 			});
-		let exit = self.on_exit().map(Ok::<_, ()>).compat();
-		let task = essential_task.select(exit).then(|_| Ok(()));
+		let task = select(self.on_exit(), essential_task).map(drop);
 
-		let _ = self.to_spawn_tx.unbounded_send(Box::new(task));
+		let _ = self.to_spawn_tx.unbounded_send(Box::pin(task));
 	}
 
 	fn spawn_task_handle(&self) -> SpawnTaskHandle {
@@ -276,8 +267,12 @@ where
 		}
 	}
 
-	fn rpc_query(&self, mem: &RpcSession, request: &str) -> Box<dyn Future<Item = Option<String>, Error = ()> + Send> {
-		Box::new(self.rpc_handlers.handle_request(request, mem.metadata.clone()))
+	fn rpc_query(&self, mem: &RpcSession, request: &str) -> Pin<Box<dyn Future<Output = Option<String>> + Send>> {
+		Box::pin(
+			self.rpc_handlers.handle_request(request, mem.metadata.clone())
+				.compat()
+				.map(|res| res.expect("this should never fail"))
+		)
 	}
 
 	fn client(&self) -> Arc<sc_client::Client<Self::Backend, Self::CallExecutor, Self::Block, Self::RuntimeApi>> {
@@ -309,57 +304,56 @@ where
 	}
 }
 
-impl<TBl, TCl, TSc, TNetStatus, TNet, TTxPool, TOc> Future for
+impl<TBl: Unpin, TCl, TSc: Unpin, TNetStatus, TNet, TTxPool, TOc> Future for
 	Service<TBl, TCl, TSc, TNetStatus, TNet, TTxPool, TOc>
 {
-	type Item = ();
-	type Error = Error;
+	type Output = Result<(), Error>;
 
-	fn poll(&mut self) -> Poll<Self::Item, Self::Error> {
-		match self.essential_failed_rx.poll() {
-			Ok(Async::NotReady) => {},
-			Ok(Async::Ready(_)) | Err(_) => {
+	fn poll(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Self::Output> {
+		let this = Pin::into_inner(self);
+
+		match Pin::new(&mut this.essential_failed_rx).poll_next(cx) {
+			Poll::Pending => {},
+			Poll::Ready(_) => {
 				// Ready(None) should not be possible since we hold a live
 				// sender.
-				return Err(Error::Other("Essential task failed.".into()));
+				return Poll::Ready(Err(Error::Other("Essential task failed.".into())));
 			}
 		}
 
-		while let Ok(Async::Ready(Some(task_to_spawn))) = self.to_spawn_rx.poll() {
+		while let Poll::Ready(Some(task_to_spawn)) = Pin::new(&mut this.to_spawn_rx).poll_next(cx) {
+			// TODO: Update to tokio 0.2 when libp2p get switched to std futures (#4383)
 			let executor = tokio_executor::DefaultExecutor::current();
-			if let Err(err) = executor.execute(task_to_spawn) {
+			use futures01::future::Executor;
+			if let Err(err) = executor.execute(task_to_spawn.unit_error().compat()) {
 				debug!(
 					target: "service",
 					"Failed to spawn background task: {:?}; falling back to manual polling",
 					err
 				);
-				self.to_poll.push(err.into_future());
+				this.to_poll.push(Box::pin(err.into_future().compat().map(drop)));
 			}
 		}
 
 		// Polling all the `to_poll` futures.
-		while let Some(pos) = self.to_poll.iter_mut().position(|t| t.poll().map(|t| t.is_ready()).unwrap_or(true)) {
-			let _ = self.to_poll.remove(pos);
+		while let Some(pos) = this.to_poll.iter_mut().position(|t| Pin::new(t).poll(cx).is_ready()) {
+			let _ = this.to_poll.remove(pos);
 		}
 
 		// The service future never ends.
-		Ok(Async::NotReady)
+		Poll::Pending
 	}
 }
 
-impl<TBl, TCl, TSc, TNetStatus, TNet, TTxPool, TOc> Executor<Box<dyn Future<Item = (), Error = ()> + Send>> for
+impl<TBl, TCl, TSc, TNetStatus, TNet, TTxPool, TOc> Spawn for
 	Service<TBl, TCl, TSc, TNetStatus, TNet, TTxPool, TOc>
 {
-	fn execute(
+	fn spawn_obj(
 		&self,
-		future: Box<dyn Future<Item = (), Error = ()> + Send>
-	) -> Result<(), futures::future::ExecuteError<Box<dyn Future<Item = (), Error = ()> + Send>>> {
-		if let Err(err) = self.to_spawn_tx.unbounded_send(future) {
-			let kind = futures::future::ExecuteErrorKind::Shutdown;
-			Err(futures::future::ExecuteError::new(kind, err.into_inner()))
-		} else {
-			Ok(())
-		}
+		future: FutureObj<'static, ()>
+	) -> Result<(), SpawnError> {
+		self.to_spawn_tx.unbounded_send(Box::pin(future))
+			.map_err(|_| SpawnError::shutdown())
 	}
 }
 
@@ -376,29 +370,23 @@ fn build_network_future<
 	mut network: sc_network::NetworkWorker<B, S, H>,
 	client: Arc<C>,
 	status_sinks: Arc<Mutex<status_sinks::StatusSinks<(NetworkStatus<B>, NetworkState)>>>,
-	rpc_rx: futures03::channel::mpsc::UnboundedReceiver<sc_rpc::system::Request<B>>,
+	mut rpc_rx: mpsc::UnboundedReceiver<sc_rpc::system::Request<B>>,
 	should_have_peers: bool,
-) -> impl Future<Item = (), Error = ()> {
-	// Compatibility shim while we're transitioning to stable Futures.
-	// See https://github.com/paritytech/substrate/issues/3099
-	let mut rpc_rx = futures03::compat::Compat::new(rpc_rx.map(|v| Ok::<_, ()>(v)));
+) -> impl Future<Output = ()> {
+	let mut imported_blocks_stream = client.import_notification_stream().fuse();
+	let mut finality_notification_stream = client.finality_notification_stream().fuse();
 
-	let mut imported_blocks_stream = client.import_notification_stream().fuse()
-		.map(|v| Ok::<_, ()>(v)).compat();
-	let mut finality_notification_stream = client.finality_notification_stream().fuse()
-		.map(|v| Ok::<_, ()>(v)).compat();
-
-	futures::future::poll_fn(move || {
+	futures::future::poll_fn(move |cx| {
 		let before_polling = Instant::now();
 
 		// We poll `imported_blocks_stream`.
-		while let Ok(Async::Ready(Some(notification))) = imported_blocks_stream.poll() {
+		while let Poll::Ready(Some(notification)) = Pin::new(&mut imported_blocks_stream).poll_next(cx) {
 			network.on_block_imported(notification.hash, notification.header, Vec::new(), notification.is_new_best);
 		}
 
 		// We poll `finality_notification_stream`, but we only take the last event.
 		let mut last = None;
-		while let Ok(Async::Ready(Some(item))) = finality_notification_stream.poll() {
+		while let Poll::Ready(Some(item)) = Pin::new(&mut finality_notification_stream).poll_next(cx) {
 			last = Some(item);
 		}
 		if let Some(notification) = last {
@@ -406,7 +394,7 @@ fn build_network_future<
 		}
 
 		// Poll the RPC requests and answer them.
-		while let Ok(Async::Ready(Some(request))) = rpc_rx.poll() {
+		while let Poll::Ready(Some(request)) = Pin::new(&mut rpc_rx).poll_next(cx) {
 			match request {
 				sc_rpc::system::Request::Health(sender) => {
 					let _ = sender.send(sc_rpc::system::Health {
@@ -466,7 +454,7 @@ fn build_network_future<
 		}
 
 		// Interval report for the external API.
-		status_sinks.lock().poll(|| {
+		status_sinks.lock().poll(cx, || {
 			let status = NetworkStatus {
 				sync_state: network.sync_state(),
 				best_seen_block: network.best_seen_block(),
@@ -481,12 +469,10 @@ fn build_network_future<
 		});
 
 		// Main network polling.
-		let mut net_poll = futures03::future::poll_fn(|cx| futures03::future::Future::poll(Pin::new(&mut network), cx))
-			.compat();
-		if let Ok(Async::Ready(())) = net_poll.poll().map_err(|err| {
+		if let Poll::Ready(Ok(())) = Pin::new(&mut network).poll(cx).map_err(|err| {
 			warn!(target: "service", "Error in network: {:?}", err);
 		}) {
-			return Ok(Async::Ready(()));
+			return Poll::Ready(());
 		}
 
 		// Now some diagnostic for performances.
@@ -498,7 +484,7 @@ fn build_network_future<
 			polling_dur
 		);
 
-		Ok(Async::NotReady)
+		Poll::Pending
 	})
 }
 
@@ -596,7 +582,7 @@ impl RpcSession {
 	/// messages.
 	///
 	/// The `RpcSession` must be kept alive in order to receive messages on the sender.
-	pub fn new(sender: mpsc::Sender<String>) -> RpcSession {
+	pub fn new(sender: futures01::sync::mpsc::Sender<String>) -> RpcSession {
 		RpcSession {
 			metadata: sender.into(),
 		}
@@ -668,7 +654,7 @@ where
 				let best_block_id = BlockId::hash(self.client.info().best_hash);
 				let import_future = self.pool.submit_one(&best_block_id, uxt);
 				let import_future = import_future
-					.then(move |import_result| {
+					.map(move |import_result| {
 						match import_result {
 							Ok(_) => report_handle.report_peer(who, reputation_change_good),
 							Err(e) => match e.into_pool_error() {
@@ -680,11 +666,9 @@ where
 								Err(e) => debug!("Error converting pool error: {:?}", e),
 							}
 						}
-						ready(Ok(()))
-					})
-					.compat();
+					});
 
-				if let Err(e) = self.executor.execute(Box::new(import_future)) {
+				if let Err(e) = self.executor.spawn(Box::new(import_future)) {
 					warn!("Error scheduling extrinsic import: {:?}", e);
 				}
 			}
@@ -700,7 +684,7 @@ where
 #[cfg(test)]
 mod tests {
 	use super::*;
-	use futures03::executor::block_on;
+	use futures::executor::block_on;
 	use sp_consensus::SelectChain;
 	use sp_runtime::traits::BlindCheckable;
 	use substrate_test_runtime_client::{prelude::*, runtime::{Extrinsic, Transfer}};
diff --git a/client/service/src/status_sinks.rs b/client/service/src/status_sinks.rs
index 205a22d70f9f4..de5fe865736af 100644
--- a/client/service/src/status_sinks.rs
+++ b/client/service/src/status_sinks.rs
@@ -14,11 +14,11 @@
 // You should have received a copy of the GNU General Public License
 // along with Substrate.  If not, see <http://www.gnu.org/licenses/>.
 
-use futures::prelude::*;
-use futures::sync::mpsc;
-use futures::stream::futures_unordered::FuturesUnordered;
-use std::time::{Duration, Instant};
-use tokio_timer::Delay;
+use futures::{Stream, stream::futures_unordered::FuturesUnordered, channel::mpsc};
+use std::time::Duration;
+use std::pin::Pin;
+use std::task::{Poll, Context};
+use futures_timer::Delay;
 
 /// Holds a list of `UnboundedSender`s, each associated with a certain time period. Every time the
 /// period elapses, we push an element on the sender.
@@ -29,7 +29,7 @@ pub struct StatusSinks<T> {
 }
 
 struct YieldAfter<T> {
-	delay: tokio_timer::Delay,
+	delay: Delay,
 	interval: Duration,
 	sender: Option<mpsc::UnboundedSender<T>>,
 }
@@ -47,7 +47,7 @@ impl<T> StatusSinks<T> {
 	/// The `interval` is the time period between two pushes on the sender.
 	pub fn push(&mut self, interval: Duration, sender: mpsc::UnboundedSender<T>) {
 		self.entries.push(YieldAfter {
-			delay: Delay::new(Instant::now() + interval),
+			delay: Delay::new(interval),
 			interval,
 			sender: Some(sender),
 		})
@@ -57,16 +57,16 @@ impl<T> StatusSinks<T> {
 	/// pushes what it returns to the sender.
 	///
 	/// This function doesn't return anything, but it should be treated as if it implicitly
-	/// returns `Ok(Async::NotReady)`. In particular, it should be called again when the task
+	/// returns `Poll::Pending`. In particular, it should be called again when the task
 	/// is waken up.
 	///
 	/// # Panic
 	///
 	/// Panics if not called within the context of a task.
-	pub fn poll(&mut self, mut status_grab: impl FnMut() -> T) {
+	pub fn poll(&mut self, cx: &mut Context, mut status_grab: impl FnMut() -> T) {
 		loop {
-			match self.entries.poll() {
-				Ok(Async::Ready(Some((sender, interval)))) => {
+			match Pin::new(&mut self.entries).poll_next(cx) {
+				Poll::Ready(Some((sender, interval))) => {
 					let status = status_grab();
 					if sender.unbounded_send(status).is_ok() {
 						self.entries.push(YieldAfter {
@@ -74,33 +74,32 @@ impl<T> StatusSinks<T> {
 							// waken up and the moment it is polled, the period is actually not
 							// `interval` but `interval + <delay>`. We ignore this problem in
 							// practice.
-							delay: Delay::new(Instant::now() + interval),
+							delay: Delay::new(interval),
 							interval,
 							sender: Some(sender),
 						});
 					}
 				}
-				Err(()) |
-				Ok(Async::Ready(None)) |
-				Ok(Async::NotReady) => break,
+				Poll::Ready(None) |
+				Poll::Pending => break,
 			}
 		}
 	}
 }
 
-impl<T> Future for YieldAfter<T> {
-	type Item = (mpsc::UnboundedSender<T>, Duration);
-	type Error = ();
+impl<T> futures::Future for YieldAfter<T> {
+	type Output = (mpsc::UnboundedSender<T>, Duration);
 
-	fn poll(&mut self) -> Poll<Self::Item, Self::Error> {
-		match self.delay.poll() {
-			Ok(Async::NotReady) => Ok(Async::NotReady),
-			Ok(Async::Ready(())) => {
-				let sender = self.sender.take()
+	fn poll(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Self::Output> {
+		let this = Pin::into_inner(self);
+
+		match Pin::new(&mut this.delay).poll(cx) {
+			Poll::Pending => Poll::Pending,
+			Poll::Ready(()) => {
+				let sender = this.sender.take()
 					.expect("sender is always Some unless the future is finished; qed");
-				Ok(Async::Ready((sender, self.interval)))
-			},
-			Err(_) => Err(()),
+				Poll::Ready((sender, this.interval))
+			}
 		}
 	}
 }
@@ -109,8 +108,9 @@ impl<T> Future for YieldAfter<T> {
 mod tests {
 	use super::StatusSinks;
 	use futures::prelude::*;
-	use futures::sync::mpsc;
+	use futures::channel::mpsc;
 	use std::time::Duration;
+	use std::task::Poll;
 
 	#[test]
 	fn works() {
@@ -125,18 +125,18 @@ mod tests {
 		let mut runtime = tokio::runtime::Runtime::new().unwrap();
 
 		let mut val_order = 5;
-		runtime.spawn(futures::future::poll_fn(move || {
-			status_sinks.poll(|| { val_order += 1; val_order });
-			Ok(Async::NotReady)
+		runtime.spawn(futures::future::poll_fn(move |cx| {
+			status_sinks.poll(cx, || { val_order += 1; val_order });
+			Poll::<()>::Pending
 		}));
 
 		let done = rx
 			.into_future()
-			.and_then(|(item, rest)| {
+			.then(|(item, rest)| {
 				assert_eq!(item, Some(6));
 				rest.into_future()
 			})
-			.and_then(|(item, rest)| {
+			.then(|(item, rest)| {
 				assert_eq!(item, Some(7));
 				rest.into_future()
 			})
@@ -144,6 +144,6 @@ mod tests {
 				assert_eq!(item, Some(8));
 			});
 
-		runtime.block_on(done).unwrap();
+		runtime.block_on(done);
 	}
 }
diff --git a/client/service/test/Cargo.toml b/client/service/test/Cargo.toml
index 2789bfda0fe19..01ccf71a4bd7b 100644
--- a/client/service/test/Cargo.toml
+++ b/client/service/test/Cargo.toml
@@ -7,15 +7,15 @@ edition = "2018"
 [dependencies]
 tempfile = "3.1.0"
 tokio = "0.1.22"
-futures = "0.1.29"
+futures01 = { package = "futures", version = "0.1.29" }
 log = "0.4.8"
 env_logger = "0.7.0"
 fdlimit = "0.1.1"
-futures03 = { package = "futures", version = "0.3.1", features = ["compat"] }
-sc-service = { version = "2.0.0", default-features = false, path = "../../service" }
+futures = { version = "0.3.1", features = ["compat"] }
+sc-service = { version = "0.8.0", default-features = false, path = "../../service" }
 sc-network = { version = "0.8", path = "../../network" }
 sp-consensus = { version = "0.8", path = "../../../primitives/consensus/common" }
-sc-client = { version = "2.0.0", path = "../../" }
+sc-client = { version = "0.8", path = "../../" }
 sp-runtime = { version = "2.0.0", path = "../../../primitives/runtime" }
 sp-core = { version = "2.0.0", path = "../../../primitives/core" }
 sp-transaction-pool = { version = "2.0.0", path = "../../../primitives/transaction-pool" }
diff --git a/client/service/test/src/lib.rs b/client/service/test/src/lib.rs
index c8dead0845c65..c9a01b2b2f2c8 100644
--- a/client/service/test/src/lib.rs
+++ b/client/service/test/src/lib.rs
@@ -21,7 +21,7 @@ use std::sync::{Arc, Mutex, MutexGuard};
 use std::net::Ipv4Addr;
 use std::time::Duration;
 use log::info;
-use futures::{Future, Stream, Poll};
+use futures01::{Future, Stream, Poll};
 use tempfile::TempDir;
 use tokio::{runtime::Runtime, prelude::FutureExt};
 use tokio::timer::Interval;
@@ -72,12 +72,13 @@ impl<T> From<T> for SyncService<T> {
 	}
 }
 
-impl<T: Future<Item=(), Error=sc_service::Error>> Future for SyncService<T> {
+impl<T: futures::Future<Output=Result<(), sc_service::Error>> + Unpin> Future for SyncService<T> {
 	type Item = ();
 	type Error = sc_service::Error;
 
 	fn poll(&mut self) -> Poll<Self::Item, Self::Error> {
-		self.0.lock().unwrap().poll()
+		let mut f = self.0.lock().unwrap();
+		futures::compat::Compat::new(&mut *f).poll()
 	}
 }
 
@@ -458,7 +459,7 @@ pub fn sync<G, E, Fb, F, Lb, L, B, ExF, U>(
 	let first_user_data = &network.full_nodes[0].2;
 	let best_block = BlockId::number(first_service.get().client().chain_info().best_number);
 	let extrinsic = extrinsic_factory(&first_service.get(), first_user_data);
-	futures03::executor::block_on(first_service.get().transaction_pool().submit_one(&best_block, extrinsic)).unwrap();
+	futures::executor::block_on(first_service.get().transaction_pool().submit_one(&best_block, extrinsic)).unwrap();
 	network.run_until_all_full(
 		|_index, service| service.get().transaction_pool().ready().count() == 1,
 		|_index, _service| true,
diff --git a/client/src/call_executor.rs b/client/src/call_executor.rs
index 6a41eba0108c0..6c685fc1b82c7 100644
--- a/client/src/call_executor.rs
+++ b/client/src/call_executor.rs
@@ -17,7 +17,7 @@
 use std::{sync::Arc, panic::UnwindSafe, result, cell::RefCell};
 use codec::{Encode, Decode};
 use sp_runtime::{
-	generic::BlockId, traits::{Block as BlockT, HasherFor},
+	generic::BlockId, traits::{Block as BlockT, HasherFor, NumberFor},
 };
 use sp_state_machine::{
 	self, OverlayedChanges, Ext, ExecutionManager, StateMachine, ExecutionStrategy,
@@ -61,7 +61,7 @@ impl<B, E> Clone for LocalCallExecutor<B, E> where E: Clone {
 impl<B, E, Block> CallExecutor<Block> for LocalCallExecutor<B, E>
 where
 	B: backend::Backend<Block>,
-	E: CodeExecutor + RuntimeInfo,
+	E: CodeExecutor + RuntimeInfo + Clone + 'static,
 	Block: BlockT,
 {
 	type Error = E::Error;
@@ -80,7 +80,7 @@ where
 		let state = self.backend.state_at(*id)?;
 		let return_data = StateMachine::new(
 			&state,
-			self.backend.changes_trie_storage(),
+			backend::changes_tries_state_at_block(id, self.backend.changes_trie_storage())?,
 			&mut changes,
 			&self.executor,
 			method,
@@ -132,6 +132,7 @@ where
 		}
 
 		let mut state = self.backend.state_at(*at)?;
+		let changes_trie_state = backend::changes_tries_state_at_block(at, self.backend.changes_trie_storage())?;
 
 		let mut storage_transaction_cache = storage_transaction_cache.map(|c| c.borrow_mut());
 
@@ -150,7 +151,7 @@ where
 
 				StateMachine::new(
 					&backend,
-					self.backend.changes_trie_storage(),
+					changes_trie_state,
 					&mut *changes.borrow_mut(),
 					&self.executor,
 					method,
@@ -163,7 +164,7 @@ where
 			}
 			None => StateMachine::new(
 				&state,
-				self.backend.changes_trie_storage(),
+				changes_trie_state,
 				&mut *changes.borrow_mut(),
 				&self.executor,
 				method,
@@ -183,13 +184,13 @@ where
 	fn runtime_version(&self, id: &BlockId<Block>) -> sp_blockchain::Result<RuntimeVersion> {
 		let mut overlay = OverlayedChanges::default();
 		let state = self.backend.state_at(*id)?;
+		let changes_trie_state = backend::changes_tries_state_at_block(id, self.backend.changes_trie_storage())?;
 		let mut cache = StorageTransactionCache::<Block, B::State>::default();
-
 		let mut ext = Ext::new(
 			&mut overlay,
 			&mut cache,
 			&state,
-			self.backend.changes_trie_storage(),
+			changes_trie_state,
 			None,
 		);
 		let version = self.executor.runtime_version(&mut ext);
@@ -207,7 +208,7 @@ where
 		method: &str,
 		call_data: &[u8]
 	) -> Result<(Vec<u8>, StorageProof), sp_blockchain::Error> {
-		sp_state_machine::prove_execution_on_trie_backend(
+		sp_state_machine::prove_execution_on_trie_backend::<_, _, NumberFor<Block>, _>(
 			trie_state,
 			overlay,
 			&self.executor,
@@ -225,7 +226,7 @@ where
 impl<B, E, Block> sp_version::GetRuntimeVersion<Block> for LocalCallExecutor<B, E>
 	where
 		B: backend::Backend<Block>,
-		E: CodeExecutor + RuntimeInfo,
+		E: CodeExecutor + RuntimeInfo + Clone + 'static,
 		Block: BlockT,
 {
 	fn native_version(&self) -> &sp_version::NativeVersion {
diff --git a/client/src/client.rs b/client/src/client.rs
index 2babf6f3e900e..c74a005c6fea6 100644
--- a/client/src/client.rs
+++ b/client/src/client.rs
@@ -66,6 +66,7 @@ pub use sc_client_api::{
 	backend::{
 		self, BlockImportOperation, PrunableStateChangesTrieStorage,
 		ClientImportOperation, Finalizer, ImportSummary, NewBlockState,
+		changes_tries_state_at_block,
 	},
 	client::{
 		ImportNotifications, FinalityNotification, FinalityNotifications, BlockImportNotification,
@@ -129,7 +130,7 @@ impl<H> PrePostHeader<H> {
 /// Create an instance of in-memory client.
 pub fn new_in_mem<E, Block, S, RA>(
 	executor: E,
-	genesis_storage: S,
+	genesis_storage: &S,
 	keystore: Option<sp_core::traits::BareCryptoStorePtr>,
 ) -> sp_blockchain::Result<Client<
 	in_mem::Backend<Block>,
@@ -149,14 +150,14 @@ pub fn new_in_mem<E, Block, S, RA>(
 pub fn new_with_backend<B, E, Block, S, RA>(
 	backend: Arc<B>,
 	executor: E,
-	build_genesis_storage: S,
+	build_genesis_storage: &S,
 	keystore: Option<sp_core::traits::BareCryptoStorePtr>,
 ) -> sp_blockchain::Result<Client<B, LocalCallExecutor<B, E>, Block, RA>>
 	where
 		E: CodeExecutor + RuntimeInfo,
 		S: BuildStorage,
 		Block: BlockT,
-		B: backend::LocalBackend<Block>
+		B: backend::LocalBackend<Block> + 'static,
 {
 	let call_executor = LocalCallExecutor::new(backend.clone(), executor);
 	let extensions = ExecutionExtensions::new(Default::default(), keystore);
@@ -187,7 +188,7 @@ impl<B, E, Block, RA> Client<B, E, Block, RA> where
 	pub fn new<S: BuildStorage>(
 		backend: Arc<B>,
 		executor: E,
-		build_genesis_storage: S,
+		build_genesis_storage: &S,
 		fork_blocks: ForkBlocks<Block>,
 		bad_blocks: BadBlocks<Block>,
 		execution_extensions: ExecutionExtensions<Block>,
@@ -407,18 +408,26 @@ impl<B, E, Block, RA> Client<B, E, Block, RA> where
 		first: NumberFor<Block>,
 		last: BlockId<Block>,
 	) -> sp_blockchain::Result<Option<(NumberFor<Block>, BlockId<Block>)>> {
-		let (config, storage) = match self.require_changes_trie().ok() {
-			Some((config, storage)) => (config, storage),
+		let last_number = self.backend.blockchain().expect_block_number_from_id(&last)?;
+		let last_hash = self.backend.blockchain().expect_block_hash_from_id(&last)?;
+		if first > last_number {
+			return Err(sp_blockchain::Error::ChangesTrieAccessFailed("Invalid changes trie range".into()));
+		}
+
+		let (storage, configs) = match self.require_changes_trie(first, last_hash, false).ok() {
+			Some((storage, configs)) => (storage, configs),
 			None => return Ok(None),
 		};
-		let last_num = self.backend.blockchain().expect_block_number_from_id(&last)?;
-		if first > last_num {
-			return Err(sp_blockchain::Error::ChangesTrieAccessFailed("Invalid changes trie range".into()));
+
+		let first_available_changes_trie = configs.last().map(|config| config.0);
+		match first_available_changes_trie {
+			Some(first_available_changes_trie) => {
+				let oldest_unpruned = storage.oldest_pruned_digest_range_end();
+				let first = std::cmp::max(first_available_changes_trie, oldest_unpruned);
+				Ok(Some((first, last)))
+			},
+			None => Ok(None)
 		}
-		let finalized_number = self.backend.blockchain().info().finalized_number;
-		let oldest = storage.oldest_changes_trie_block(&config, finalized_number);
-		let first = ::std::cmp::max(first, oldest);
-		Ok(Some((first, last)))
 	}
 
 	/// Get pairs of (block, extrinsic) where key has been changed at given blocks range.
@@ -432,30 +441,42 @@ impl<B, E, Block, RA> Client<B, E, Block, RA> where
 		storage_key: Option<&StorageKey>,
 		key: &StorageKey
 	) -> sp_blockchain::Result<Vec<(NumberFor<Block>, u32)>> {
-		let (config, storage) = self.require_changes_trie()?;
 		let last_number = self.backend.blockchain().expect_block_number_from_id(&last)?;
 		let last_hash = self.backend.blockchain().expect_block_hash_from_id(&last)?;
+		let (storage, configs) = self.require_changes_trie(first, last_hash, true)?;
+
+		let mut result = Vec::new();
+		let best_number = self.backend.blockchain().info().best_number;
+		for (config_zero, config_end, config) in configs {
+			let range_first = ::std::cmp::max(first, config_zero + One::one());
+			let range_anchor = match config_end {
+				Some((config_end_number, config_end_hash)) => if last_number > config_end_number {
+					ChangesTrieAnchorBlockId { hash: config_end_hash, number: config_end_number }
+				} else {
+					ChangesTrieAnchorBlockId { hash: convert_hash(&last_hash), number: last_number }
+				},
+				None => ChangesTrieAnchorBlockId { hash: convert_hash(&last_hash), number: last_number },
+			};
 
-		// FIXME: remove this in https://github.com/paritytech/substrate/pull/3201
-		let config_range = ChangesTrieConfigurationRange {
-			config: &config,
-			zero: Zero::zero(),
-			end: None,
-		};
+			let config_range = ChangesTrieConfigurationRange {
+				config: &config,
+				zero: config_zero.clone(),
+				end: config_end.map(|(config_end_number, _)| config_end_number),
+			};
+			let result_range: Vec<(NumberFor<Block>, u32)> = key_changes::<HasherFor<Block>, _>(
+				config_range,
+				storage.storage(),
+				range_first,
+				&range_anchor,
+				best_number,
+				storage_key.as_ref().map(|x| &x.0[..]),
+				&key.0)
+			.and_then(|r| r.map(|r| r.map(|(block, tx)| (block, tx))).collect::<Result<_, _>>())
+			.map_err(|err| sp_blockchain::Error::ChangesTrieAccessFailed(err))?;
+			result.extend(result_range);
+		}
 
-		key_changes::<HasherFor<Block>, _>(
-			config_range,
-			&*storage,
-			first,
-			&ChangesTrieAnchorBlockId {
-				hash: convert_hash(&last_hash),
-				number: last_number,
-			},
-			self.backend.blockchain().info().best_number,
-			storage_key.as_ref().map(|sk| sk.0.as_slice()),
-			&key.0)
-		.and_then(|r| r.map(|r| r.map(|(block, tx)| (block, tx))).collect::<Result<_, _>>())
-		.map_err(|err| sp_blockchain::Error::ChangesTrieAccessFailed(err))
+		Ok(result)
 	}
 
 	/// Get proof for computation of (block, extrinsic) pairs where key has been changed at given blocks range.
@@ -550,11 +571,13 @@ impl<B, E, Block, RA> Client<B, E, Block, RA> where
 			}
 		}
 
-		let (config, storage) = self.require_changes_trie()?;
+		let first_number = self.backend.blockchain()
+			.expect_block_number_from_id(&BlockId::Hash(first))?;
+		let (storage, configs) = self.require_changes_trie(first_number, last, true)?;
 		let min_number = self.backend.blockchain().expect_block_number_from_id(&BlockId::Hash(min))?;
 
 		let recording_storage = AccessedRootsRecorder::<Block> {
-			storage,
+			storage: storage.storage(),
 			min: min_number,
 			required_roots_proofs: Mutex::new(BTreeMap::new()),
 		};
@@ -564,31 +587,31 @@ impl<B, E, Block, RA> Client<B, E, Block, RA> where
 			self.backend.blockchain().expect_block_number_from_id(&BlockId::Hash(max))?,
 		);
 
-		// FIXME: remove this in https://github.com/paritytech/substrate/pull/3201
-		let config_range = ChangesTrieConfigurationRange {
-			config: &config,
-			zero: Zero::zero(),
-			end: None,
-		};
-
 		// fetch key changes proof
-		let first_number = self.backend.blockchain()
-			.expect_block_number_from_id(&BlockId::Hash(first))?;
-		let last_number = self.backend.blockchain()
-			.expect_block_number_from_id(&BlockId::Hash(last))?;
-		let key_changes_proof = key_changes_proof::<HasherFor<Block>, _>(
-			config_range,
-			&recording_storage,
-			first_number,
-			&ChangesTrieAnchorBlockId {
-				hash: convert_hash(&last),
-				number: last_number,
-			},
-			max_number,
-			storage_key.as_ref().map(|sk| sk.0.as_slice()),
-			&key.0,
-		)
-		.map_err(|err| sp_blockchain::Error::from(sp_blockchain::Error::ChangesTrieAccessFailed(err)))?;
+		let mut proof = Vec::new();
+		for (config_zero, config_end, config) in configs {
+			let last_number = self.backend.blockchain()
+				.expect_block_number_from_id(&BlockId::Hash(last))?;
+			let config_range = ChangesTrieConfigurationRange {
+				config: &config,
+				zero: config_zero,
+				end: config_end.map(|(config_end_number, _)| config_end_number),
+			};
+			let proof_range = key_changes_proof::<HasherFor<Block>, _>(
+				config_range,
+				&recording_storage,
+				first_number,
+				&ChangesTrieAnchorBlockId {
+					hash: convert_hash(&last),
+					number: last_number,
+				},
+				max_number,
+				storage_key.as_ref().map(|x| &x.0[..]),
+				&key.0,
+			)
+			.map_err(|err| sp_blockchain::Error::ChangesTrieAccessFailed(err))?;
+			proof.extend(proof_range);
+		}
 
 		// now gather proofs for all changes tries roots that were touched during key_changes_proof
 		// execution AND are unknown (i.e. replaced with CHT) to the requester
@@ -597,7 +620,7 @@ impl<B, E, Block, RA> Client<B, E, Block, RA> where
 
 		Ok(ChangesProof {
 			max_block: max_number,
-			proof: key_changes_proof,
+			proof,
 			roots: roots.into_iter().map(|(n, h)| (n, convert_hash(&h))).collect(),
 			roots_proof,
 		})
@@ -650,14 +673,45 @@ impl<B, E, Block, RA> Client<B, E, Block, RA> where
 		Ok(proof)
 	}
 
-	/// Returns changes trie configuration and storage or an error if it is not supported.
-	fn require_changes_trie(&self) -> sp_blockchain::Result<(ChangesTrieConfiguration, &B::ChangesTrieStorage)> {
-		let config = self.changes_trie_config()?;
-		let storage = self.backend.changes_trie_storage();
-		match (config, storage) {
-			(Some(config), Some(storage)) => Ok((config, storage)),
-			_ => Err(sp_blockchain::Error::ChangesTriesNotSupported.into()),
+	/// Returns changes trie storage and all configurations that have been active in the range [first; last].
+	///
+	/// Configurations are returned in descending order (and obviously never overlap).
+	/// If fail_if_disabled is false, returns maximal consequent configurations ranges, starting from last and
+	/// stopping on either first, or when CT have been disabled.
+	/// If fail_if_disabled is true, fails when there's a subrange where CT have been disabled
+	/// inside first..last blocks range.
+	fn require_changes_trie(
+		&self,
+		first: NumberFor<Block>,
+		last: Block::Hash,
+		fail_if_disabled: bool,
+	) -> sp_blockchain::Result<(
+		&dyn PrunableStateChangesTrieStorage<Block>,
+		Vec<(NumberFor<Block>, Option<(NumberFor<Block>, Block::Hash)>, ChangesTrieConfiguration)>,
+	)> {
+		let storage = match self.backend.changes_trie_storage() {
+			Some(storage) => storage,
+			None => return Err(sp_blockchain::Error::ChangesTriesNotSupported),
+		};
+
+		let mut configs = Vec::with_capacity(1);
+		let mut current = last;
+		loop {
+			let config_range = storage.configuration_at(&BlockId::Hash(current))?;
+			match config_range.config {
+				Some(config) => configs.push((config_range.zero.0, config_range.end, config)),
+				None if !fail_if_disabled => return Ok((storage, configs)),
+				None => return Err(sp_blockchain::Error::ChangesTriesNotSupported),
+			}
+
+			if config_range.zero.0 < first {
+				break;
+			}
+
+			current = *self.backend.blockchain().expect_header(BlockId::Hash(config_range.zero.1))?.parent_hash();
 		}
+
+		Ok((storage, configs))
 	}
 
 	/// Create a new block, built on the head of the chain.
@@ -750,7 +804,6 @@ impl<B, E, Block, RA> Client<B, E, Block, RA> where
 		import_block: BlockImportParams<Block, backend::TransactionFor<B, Block>>,
 		new_cache: HashMap<CacheKeyId, Vec<u8>>,
 	) -> sp_blockchain::Result<ImportResult> where
-		E: CallExecutor<Block> + Send + Sync + Clone,
 		Self: ProvideRuntimeApi<Block>,
 		<Self as ProvideRuntimeApi<Block>>::Api: CoreApi<Block, Error = Error> +
 			ApiExt<Block, StateBackend = B::State>,
@@ -829,7 +882,6 @@ impl<B, E, Block, RA> Client<B, E, Block, RA> where
 		fork_choice: ForkChoiceStrategy,
 		import_existing: bool,
 	) -> sp_blockchain::Result<ImportResult> where
-		E: CallExecutor<Block> + Send + Sync + Clone,
 		Self: ProvideRuntimeApi<Block>,
 		<Self as ProvideRuntimeApi<Block>>::Api: CoreApi<Block, Error = Error> +
 				ApiExt<Block, StateBackend = B::State>,
@@ -990,10 +1042,14 @@ impl<B, E, Block, RA> Client<B, E, Block, RA> where
 				)?;
 
 				let state = self.backend.state_at(at)?;
+				let changes_trie_state = changes_tries_state_at_block(
+					&at,
+					self.backend.changes_trie_storage(),
+				)?;
 
 				let gen_storage_changes = runtime_api.into_storage_changes(
 					&state,
-					self.backend.changes_trie_storage(),
+					changes_trie_state.as_ref(),
 					*parent_hash,
 				);
 
@@ -1251,13 +1307,6 @@ impl<B, E, Block, RA> Client<B, E, Block, RA> where
 		Ok(uncles)
 	}
 
-	fn changes_trie_config(&self) -> Result<Option<ChangesTrieConfiguration>, Error> {
-		Ok(self.backend.state_at(BlockId::Number(self.backend.blockchain().info().best_number))?
-			.storage(well_known_keys::CHANGES_TRIE_CONFIG)
-			.map_err(|e| sp_blockchain::Error::from_state(Box::new(e)))?
-			.and_then(|c| Decode::decode(&mut &*c).ok()))
-	}
-
 	/// Prepare in-memory header that is used in execution environment.
 	fn prepare_environment_block(&self, parent: &BlockId<Block>) -> sp_blockchain::Result<Block::Header> {
 		let parent_header = self.backend.blockchain().expect_header(*parent)?;
@@ -1387,7 +1436,7 @@ impl<B, E, Block, RA> ProvideCache<Block> for Client<B, E, Block, RA> where
 
 impl<B, E, Block, RA> ProvideRuntimeApi<Block> for Client<B, E, Block, RA> where
 	B: backend::Backend<Block>,
-	E: CallExecutor<Block, Backend = B> + Clone + Send + Sync,
+	E: CallExecutor<Block, Backend = B> + Send + Sync,
 	Block: BlockT,
 	RA: ConstructRuntimeApi<Block, Self>,
 {
@@ -1400,7 +1449,7 @@ impl<B, E, Block, RA> ProvideRuntimeApi<Block> for Client<B, E, Block, RA> where
 
 impl<B, E, Block, RA> CallApiAt<Block> for Client<B, E, Block, RA> where
 	B: backend::Backend<Block>,
-	E: CallExecutor<Block, Backend = B> + Clone + Send + Sync,
+	E: CallExecutor<Block, Backend = B> + Send + Sync,
 	Block: BlockT,
 {
 	type Error = Error;
@@ -1448,7 +1497,7 @@ impl<B, E, Block, RA> CallApiAt<Block> for Client<B, E, Block, RA> where
 /// important verification work.
 impl<B, E, Block, RA> sp_consensus::BlockImport<Block> for &Client<B, E, Block, RA> where
 	B: backend::Backend<Block>,
-	E: CallExecutor<Block> + Clone + Send + Sync,
+	E: CallExecutor<Block> + Send + Sync,
 	Block: BlockT,
 	Client<B, E, Block, RA>: ProvideRuntimeApi<Block>,
 	<Client<B, E, Block, RA> as ProvideRuntimeApi<Block>>::Api: CoreApi<Block, Error = Error> +
@@ -1552,7 +1601,7 @@ impl<B, E, Block, RA> sp_consensus::BlockImport<Block> for &Client<B, E, Block,
 
 impl<B, E, Block, RA> sp_consensus::BlockImport<Block> for Client<B, E, Block, RA> where
 	B: backend::Backend<Block>,
-	E: CallExecutor<Block> + Clone + Send + Sync,
+	E: CallExecutor<Block> + Send + Sync,
 	Block: BlockT,
 	Self: ProvideRuntimeApi<Block>,
 	<Self as ProvideRuntimeApi<Block>>::Api: CoreApi<Block, Error = Error> +
@@ -1873,7 +1922,8 @@ pub(crate) mod tests {
 
 		// prepare client ang import blocks
 		let mut local_roots = Vec::new();
-		let mut remote_client = TestClientBuilder::new().set_support_changes_trie(true).build();
+		let config = Some(ChangesTrieConfiguration::new(4, 2));
+		let mut remote_client = TestClientBuilder::new().changes_trie_config(config).build();
 		let mut nonces: HashMap<_, u64> = Default::default();
 		for (i, block_transfers) in blocks_transfers.into_iter().enumerate() {
 			let mut builder = remote_client.new_block(Default::default()).unwrap();
@@ -2909,13 +2959,15 @@ pub(crate) mod tests {
 			.unwrap().build().unwrap().block;
 		client.import(BlockOrigin::Own, b2.clone()).unwrap();
 
+		// prepare B3 before we finalize A2, because otherwise we won't be able to
+		// read changes trie configuration after A2 is finalized
+		let b3 = client.new_block_at(&BlockId::Hash(b2.hash()), Default::default(), false)
+			.unwrap().build().unwrap().block;
+
 		// we will finalize A2 which should make it impossible to import a new
 		// B3 at the same height but that doesnt't include it
 		ClientExt::finalize_block(&client, BlockId::Hash(a2.hash()), None).unwrap();
 
-		let b3 = client.new_block_at(&BlockId::Hash(b2.hash()), Default::default(), false)
-			.unwrap().build().unwrap().block;
-
 		let import_err = client.import(BlockOrigin::Own, b3).err().unwrap();
 		let expected_err = ConsensusError::ClientImport(
 			sp_blockchain::Error::NotInFinalizedChain.to_string()
@@ -3052,4 +3104,104 @@ pub(crate) mod tests {
 		check_block_b1.parent_hash = H256::random();
 		assert_eq!(client.check_block(check_block_b1.clone()).unwrap(), ImportResult::UnknownParent);
 	}
+
+	#[test]
+	fn imports_blocks_with_changes_tries_config_change() {
+		// create client with initial 4^2 configuration
+		let mut client = TestClientBuilder::with_default_backend()
+			.changes_trie_config(Some(ChangesTrieConfiguration {
+				digest_interval: 4,
+				digest_levels: 2,
+			})).build();
+
+		// ===================================================================
+		// blocks 1,2,3,4,5,6,7,8,9,10 are empty
+		// block 11 changes the key
+		// block 12 is the L1 digest that covers this change
+		// blocks 13,14,15,16,17,18,19,20,21,22 are empty
+		// block 23 changes the configuration to 5^1 AND is skewed digest
+		// ===================================================================
+		// blocks 24,25 are changing the key
+		// block 26 is empty
+		// block 27 changes the key
+		// block 28 is the L1 digest (NOT SKEWED!!!) that covers changes AND changes configuration to 3^1
+		// ===================================================================
+		// block 29 is empty
+		// block 30 changes the key
+		// block 31 is L1 digest that covers this change
+		// ===================================================================
+		(1..11).for_each(|number| {
+			let block = client.new_block_at(&BlockId::Number(number - 1), Default::default(), false)
+				.unwrap().build().unwrap().block;
+			client.import(BlockOrigin::Own, block).unwrap();
+		});
+		(11..12).for_each(|number| {
+			let mut block = client.new_block_at(&BlockId::Number(number - 1), Default::default(), false).unwrap();
+			block.push_storage_change(vec![42], Some(number.to_le_bytes().to_vec())).unwrap();
+			let block = block.build().unwrap().block;
+			client.import(BlockOrigin::Own, block).unwrap();
+		});
+		(12..23).for_each(|number| {
+			let block = client.new_block_at(&BlockId::Number(number - 1), Default::default(), false)
+				.unwrap().build().unwrap().block;
+			client.import(BlockOrigin::Own, block).unwrap();
+		});
+		(23..24).for_each(|number| {
+			let mut block = client.new_block_at(&BlockId::Number(number - 1), Default::default(), false).unwrap();
+			block.push_changes_trie_configuration_update(Some(ChangesTrieConfiguration {
+				digest_interval: 5,
+				digest_levels: 1,
+			})).unwrap();
+			let block = block.build().unwrap().block;
+			client.import(BlockOrigin::Own, block).unwrap();
+		});
+		(24..26).for_each(|number| {
+			let mut block = client.new_block_at(&BlockId::Number(number - 1), Default::default(), false).unwrap();
+			block.push_storage_change(vec![42], Some(number.to_le_bytes().to_vec())).unwrap();
+			let block = block.build().unwrap().block;
+			client.import(BlockOrigin::Own, block).unwrap();
+		});
+		(26..27).for_each(|number| {
+			let block = client.new_block_at(&BlockId::Number(number - 1), Default::default(), false)
+				.unwrap().build().unwrap().block;
+			client.import(BlockOrigin::Own, block).unwrap();
+		});
+		(27..28).for_each(|number| {
+			let mut block = client.new_block_at(&BlockId::Number(number - 1), Default::default(), false).unwrap();
+			block.push_storage_change(vec![42], Some(number.to_le_bytes().to_vec())).unwrap();
+			let block = block.build().unwrap().block;
+			client.import(BlockOrigin::Own, block).unwrap();
+		});
+		(28..29).for_each(|number| {
+			let mut block = client.new_block_at(&BlockId::Number(number - 1), Default::default(), false).unwrap();
+			block.push_changes_trie_configuration_update(Some(ChangesTrieConfiguration {
+				digest_interval: 3,
+				digest_levels: 1,
+			})).unwrap();
+			let block = block.build().unwrap().block;
+			client.import(BlockOrigin::Own, block).unwrap();
+		});
+		(29..30).for_each(|number| {
+			let block = client.new_block_at(&BlockId::Number(number - 1), Default::default(), false)
+				.unwrap().build().unwrap().block;
+			client.import(BlockOrigin::Own, block).unwrap();
+		});
+		(30..31).for_each(|number| {
+			let mut block = client.new_block_at(&BlockId::Number(number - 1), Default::default(), false).unwrap();
+			block.push_storage_change(vec![42], Some(number.to_le_bytes().to_vec())).unwrap();
+			let block = block.build().unwrap().block;
+			client.import(BlockOrigin::Own, block).unwrap();
+		});
+		(31..32).for_each(|number| {
+			let block = client.new_block_at(&BlockId::Number(number - 1), Default::default(), false)
+				.unwrap().build().unwrap().block;
+			client.import(BlockOrigin::Own, block).unwrap();
+		});
+
+		// now check that configuration cache works
+		assert_eq!(
+			client.key_changes(1, BlockId::Number(31), None, &StorageKey(vec![42])).unwrap(),
+			vec![(30, 0), (27, 0), (25, 0), (24, 0), (11, 0)]
+		);
+	}
 }
diff --git a/client/src/genesis.rs b/client/src/genesis.rs
index ab89bdd4d5e13..fccdd71817e1f 100644
--- a/client/src/genesis.rs
+++ b/client/src/genesis.rs
@@ -45,7 +45,7 @@ mod tests {
 	use codec::{Encode, Decode, Joiner};
 	use sc_executor::native_executor_instance;
 	use sp_state_machine::{
-		StateMachine, OverlayedChanges, ExecutionStrategy, InMemoryChangesTrieStorage,
+		StateMachine, OverlayedChanges, ExecutionStrategy,
 		InMemoryBackend,
 	};
 	use substrate_test_runtime_client::{
@@ -59,7 +59,7 @@ mod tests {
 	native_executor_instance!(
 		Executor,
 		substrate_test_runtime_client::runtime::api::dispatch,
-		substrate_test_runtime_client::runtime::native_version
+		substrate_test_runtime_client::runtime::native_version,
 	);
 
 	fn executor() -> sc_executor::NativeExecutor<Executor> {
@@ -92,7 +92,7 @@ mod tests {
 
 		StateMachine::new(
 			backend,
-			Some(&InMemoryChangesTrieStorage::<_, u64>::new()),
+			sp_state_machine::disabled_changes_trie_state::<_, u64>(),
 			&mut overlay,
 			&executor(),
 			"Core_initialize_block",
@@ -105,7 +105,7 @@ mod tests {
 		for tx in transactions.iter() {
 			StateMachine::new(
 				backend,
-				Some(&InMemoryChangesTrieStorage::<_, u64>::new()),
+				sp_state_machine::disabled_changes_trie_state::<_, u64>(),
 				&mut overlay,
 				&executor(),
 				"BlockBuilder_apply_extrinsic",
@@ -118,7 +118,7 @@ mod tests {
 
 		let ret_data = StateMachine::new(
 			backend,
-			Some(&InMemoryChangesTrieStorage::<_, u64>::new()),
+			sp_state_machine::disabled_changes_trie_state::<_, u64>(),
 			&mut overlay,
 			&executor(),
 			"BlockBuilder_finalize_block",
@@ -150,7 +150,7 @@ mod tests {
 	#[test]
 	fn construct_genesis_should_work_with_native() {
 		let mut storage = GenesisConfig::new(
-			false,
+			None,
 			vec![Sr25519Keyring::One.public().into(), Sr25519Keyring::Two.public().into()],
 			vec![AccountKeyring::One.into(), AccountKeyring::Two.into()],
 			1000,
@@ -165,7 +165,7 @@ mod tests {
 		let mut overlay = OverlayedChanges::default();
 		let _ = StateMachine::new(
 			&backend,
-			Some(&InMemoryChangesTrieStorage::<_, u64>::new()),
+			sp_state_machine::disabled_changes_trie_state::<_, u64>(),
 			&mut overlay,
 			&executor(),
 			"Core_execute_block",
@@ -178,7 +178,7 @@ mod tests {
 
 	#[test]
 	fn construct_genesis_should_work_with_wasm() {
-		let mut storage = GenesisConfig::new(false,
+		let mut storage = GenesisConfig::new(None,
 			vec![Sr25519Keyring::One.public().into(), Sr25519Keyring::Two.public().into()],
 			vec![AccountKeyring::One.into(), AccountKeyring::Two.into()],
 			1000,
@@ -193,7 +193,7 @@ mod tests {
 		let mut overlay = OverlayedChanges::default();
 		let _ = StateMachine::new(
 			&backend,
-			Some(&InMemoryChangesTrieStorage::<_, u64>::new()),
+			sp_state_machine::disabled_changes_trie_state::<_, u64>(),
 			&mut overlay,
 			&executor(),
 			"Core_execute_block",
@@ -206,7 +206,7 @@ mod tests {
 
 	#[test]
 	fn construct_genesis_with_bad_transaction_should_panic() {
-		let mut storage = GenesisConfig::new(false,
+		let mut storage = GenesisConfig::new(None,
 			vec![Sr25519Keyring::One.public().into(), Sr25519Keyring::Two.public().into()],
 			vec![AccountKeyring::One.into(), AccountKeyring::Two.into()],
 			68,
@@ -221,7 +221,7 @@ mod tests {
 		let mut overlay = OverlayedChanges::default();
 		let r = StateMachine::new(
 			&backend,
-			Some(&InMemoryChangesTrieStorage::<_, u64>::new()),
+			sp_state_machine::disabled_changes_trie_state::<_, u64>(),
 			&mut overlay,
 			&executor(),
 			"Core_execute_block",
diff --git a/client/src/in_mem.rs b/client/src/in_mem.rs
index 5d0d14c1cb1d7..dcff8102aeb6d 100644
--- a/client/src/in_mem.rs
+++ b/client/src/in_mem.rs
@@ -16,26 +16,24 @@
 
 //! In memory client backend
 
-use std::collections::{HashMap, HashSet};
+use std::collections::HashMap;
 use std::sync::Arc;
 use parking_lot::RwLock;
-use sp_core::{ChangesTrieConfiguration, storage::well_known_keys};
+use sp_core::storage::well_known_keys;
 use sp_core::offchain::storage::{
 	InMemOffchainStorage as OffchainStorage
 };
-use sp_runtime::generic::{BlockId, DigestItem};
+use sp_runtime::generic::BlockId;
 use sp_runtime::traits::{Block as BlockT, Header as HeaderT, Zero, NumberFor, HasherFor};
 use sp_runtime::{Justification, Storage};
 use sp_state_machine::{
-	InMemoryChangesTrieStorage, ChangesTrieAnchorBlockId, ChangesTrieTransaction,
-	InMemoryBackend, Backend as StateBackend,
+	ChangesTrieTransaction, InMemoryBackend, Backend as StateBackend, StorageCollection,
+	ChildStorageCollection,
 };
-use hash_db::Prefix;
-use sp_trie::MemoryDB;
 use sp_blockchain::{CachedHeaderMetadata, HeaderMetadata};
 
 use sc_client_api::{
-	backend::{self, NewBlockState, StorageCollection, ChildStorageCollection},
+	backend::{self, NewBlockState},
 	blockchain::{
 		self, BlockStatus, HeaderBackend, well_known_cache_keys::Id as CacheKeyId
 	},
@@ -466,7 +464,6 @@ pub struct BlockImportOperation<Block: BlockT> {
 	pending_cache: HashMap<CacheKeyId, Vec<u8>>,
 	old_state: InMemoryBackend<HasherFor<Block>>,
 	new_state: Option<InMemoryBackend<HasherFor<Block>>>,
-	changes_trie_update: Option<MemoryDB<HasherFor<Block>>>,
 	aux: Vec<(Vec<u8>, Option<Vec<u8>>)>,
 	finalized_blocks: Vec<(BlockId<Block>, Option<Justification>)>,
 	set_head: Option<BlockId<Block>>,
@@ -510,9 +507,8 @@ impl<Block: BlockT> backend::BlockImportOperation<Block> for BlockImportOperatio
 
 	fn update_changes_trie(
 		&mut self,
-		update: ChangesTrieTransaction<HasherFor<Block>, NumberFor<Block>>,
+		_update: ChangesTrieTransaction<HasherFor<Block>, NumberFor<Block>>,
 	) -> sp_blockchain::Result<()> {
-		self.changes_trie_update = Some(update.0);
 		Ok(())
 	}
 
@@ -569,7 +565,6 @@ impl<Block: BlockT> backend::BlockImportOperation<Block> for BlockImportOperatio
 /// > struct for testing purposes. Do **NOT** use in production.
 pub struct Backend<Block: BlockT> where Block::Hash: Ord {
 	states: RwLock<HashMap<Block::Hash, InMemoryBackend<HasherFor<Block>>>>,
-	changes_trie_storage: ChangesTrieStorage<Block>,
 	blockchain: Blockchain<Block>,
 	import_lock: RwLock<()>,
 }
@@ -579,7 +574,6 @@ impl<Block: BlockT> Backend<Block> where Block::Hash: Ord {
 	pub fn new() -> Self {
 		Backend {
 			states: RwLock::new(HashMap::new()),
-			changes_trie_storage: ChangesTrieStorage(InMemoryChangesTrieStorage::new()),
 			blockchain: Blockchain::new(),
 			import_lock: Default::default(),
 		}
@@ -606,7 +600,6 @@ impl<Block: BlockT> backend::Backend<Block> for Backend<Block> where Block::Hash
 	type BlockImportOperation = BlockImportOperation<Block>;
 	type Blockchain = Blockchain<Block>;
 	type State = InMemoryBackend<HasherFor<Block>>;
-	type ChangesTrieStorage = ChangesTrieStorage<Block>;
 	type OffchainStorage = OffchainStorage;
 
 	fn begin_operation(&self) -> sp_blockchain::Result<Self::BlockImportOperation> {
@@ -616,7 +609,6 @@ impl<Block: BlockT> backend::Backend<Block> for Backend<Block> where Block::Hash
 			pending_cache: Default::default(),
 			old_state,
 			new_state: None,
-			changes_trie_update: None,
 			aux: Default::default(),
 			finalized_blocks: Default::default(),
 			set_head: None,
@@ -647,17 +639,6 @@ impl<Block: BlockT> backend::Backend<Block> for Backend<Block> where Block::Hash
 
 			self.states.write().insert(hash, operation.new_state.unwrap_or_else(|| old_state.clone()));
 
-			let maybe_changes_trie_root = header.digest().log(DigestItem::as_changes_trie_root).cloned();
-			if let Some(changes_trie_root) = maybe_changes_trie_root {
-				if let Some(changes_trie_update) = operation.changes_trie_update {
-					self.changes_trie_storage.0.insert(
-						*header.number(),
-						changes_trie_root,
-						changes_trie_update
-					);
-				}
-			}
-
 			self.blockchain.insert(hash, header, justification, body, pending_block.state)?;
 		}
 
@@ -688,8 +669,8 @@ impl<Block: BlockT> backend::Backend<Block> for Backend<Block> where Block::Hash
 		None
 	}
 
-	fn changes_trie_storage(&self) -> Option<&Self::ChangesTrieStorage> {
-		Some(&self.changes_trie_storage)
+	fn changes_trie_storage(&self) -> Option<&dyn backend::PrunableStateChangesTrieStorage<Block>> {
+		None
 	}
 
 	fn offchain_storage(&self) -> Option<Self::OffchainStorage> {
@@ -737,66 +718,6 @@ impl<Block: BlockT> backend::RemoteBackend<Block> for Backend<Block> where Block
 	}
 }
 
-/// Prunable in-memory changes trie storage.
-pub struct ChangesTrieStorage<Block: BlockT>(
-	InMemoryChangesTrieStorage<HasherFor<Block>, NumberFor<Block>>
-);
-
-impl<Block: BlockT> backend::PrunableStateChangesTrieStorage<Block> for ChangesTrieStorage<Block> {
-	fn oldest_changes_trie_block(
-		&self,
-		_config: &ChangesTrieConfiguration,
-		_best_finalized: NumberFor<Block>,
-	) -> NumberFor<Block> {
-		Zero::zero()
-	}
-}
-
-impl<Block: BlockT> sp_state_machine::ChangesTrieRootsStorage<HasherFor<Block>, NumberFor<Block>> for
-	ChangesTrieStorage<Block>
-{
-	fn build_anchor(
-		&self,
-		_hash: Block::Hash,
-	) -> Result<sp_state_machine::ChangesTrieAnchorBlockId<Block::Hash, NumberFor<Block>>, String> {
-		Err("Dummy implementation".into())
-	}
-
-	fn root(
-		&self,
-		_anchor: &ChangesTrieAnchorBlockId<Block::Hash, NumberFor<Block>>,
-		_block: NumberFor<Block>,
-	) -> Result<Option<Block::Hash>, String> {
-		Err("Dummy implementation".into())
-	}
-}
-
-impl<Block: BlockT> sp_state_machine::ChangesTrieStorage<HasherFor<Block>, NumberFor<Block>> for
-	ChangesTrieStorage<Block>
-{
-	fn as_roots_storage(&self)
-		-> &dyn sp_state_machine::ChangesTrieRootsStorage<HasherFor<Block>, NumberFor<Block>>
-	{
-		self
-	}
-
-	fn with_cached_changed_keys(
-		&self,
-		_root: &Block::Hash,
-		_functor: &mut dyn FnMut(&HashMap<Option<Vec<u8>>, HashSet<Vec<u8>>>),
-	) -> bool {
-		false
-	}
-
-	fn get(
-		&self,
-		key: &Block::Hash,
-		prefix: Prefix,
-	) -> Result<Option<sp_state_machine::DBValue>, String> {
-		self.0.get(key, prefix)
-	}
-}
-
 /// Check that genesis storage is valid.
 pub fn check_genesis_storage(storage: &Storage) -> sp_blockchain::Result<()> {
 	if storage.top.iter().any(|(k, _)| well_known_keys::is_child_storage_key(k)) {
diff --git a/client/src/lib.rs b/client/src/lib.rs
index cfaf08ca7ef6e..db2d4785a2c98 100644
--- a/client/src/lib.rs
+++ b/client/src/lib.rs
@@ -65,7 +65,7 @@
 //! 		NativeExecutor::<LocalExecutor>::new(WasmExecutionMethod::Interpreted, None),
 //!		),
 //! 	// This parameter provides the storage for the chain genesis.
-//! 	<Storage>::default(),
+//! 	&<Storage>::default(),
 //! 	Default::default(),
 //! 	Default::default(),
 //! 	Default::default(),
diff --git a/client/src/light/backend.rs b/client/src/light/backend.rs
index 65fd94e32395c..ad9f43587e4cd 100644
--- a/client/src/light/backend.rs
+++ b/client/src/light/backend.rs
@@ -21,19 +21,23 @@ use std::collections::HashMap;
 use std::sync::Arc;
 use parking_lot::RwLock;
 
-use sp_core::storage::{ChildInfo, OwnedChildInfo};
+use codec::{Decode, Encode};
+
+use sp_core::ChangesTrieConfiguration;
+use sp_core::storage::{well_known_keys, ChildInfo, OwnedChildInfo};
 use sp_core::offchain::storage::InMemOffchainStorage;
 use sp_state_machine::{
-	Backend as StateBackend, TrieBackend, InMemoryBackend, ChangesTrieTransaction
+	Backend as StateBackend, TrieBackend, InMemoryBackend, ChangesTrieTransaction,
+	StorageCollection, ChildStorageCollection,
 };
 use sp_runtime::{generic::BlockId, Justification, Storage};
 use sp_runtime::traits::{Block as BlockT, NumberFor, Zero, Header, HasherFor};
-use crate::in_mem::{self, check_genesis_storage};
+use crate::in_mem::check_genesis_storage;
 use sp_blockchain::{Error as ClientError, Result as ClientResult};
 use sc_client_api::{
 	backend::{
 		AuxStore, Backend as ClientBackend, BlockImportOperation, RemoteBackend, NewBlockState,
-		StorageCollection, ChildStorageCollection,
+		PrunableStateChangesTrieStorage,
 	},
 	blockchain::{
 		HeaderBackend as BlockchainHeaderBackend, well_known_cache_keys,
@@ -62,6 +66,7 @@ pub struct ImportOperation<Block: BlockT, S> {
 	finalized_blocks: Vec<BlockId<Block>>,
 	set_head: Option<BlockId<Block>>,
 	storage_update: Option<InMemoryBackend<HasherFor<Block>>>,
+	changes_trie_config_update: Option<Option<ChangesTrieConfiguration>>,
 	_phantom: std::marker::PhantomData<S>,
 }
 
@@ -115,7 +120,6 @@ impl<S, Block> ClientBackend<Block> for Backend<S, HasherFor<Block>>
 	type BlockImportOperation = ImportOperation<Block, S>;
 	type Blockchain = Blockchain<S>;
 	type State = GenesisOrUnavailableState<HasherFor<Block>>;
-	type ChangesTrieStorage = in_mem::ChangesTrieStorage<Block>;
 	type OffchainStorage = InMemOffchainStorage;
 
 	fn begin_operation(&self) -> ClientResult<Self::BlockImportOperation> {
@@ -127,6 +131,7 @@ impl<S, Block> ClientBackend<Block> for Backend<S, HasherFor<Block>>
 			finalized_blocks: Vec::new(),
 			set_head: None,
 			storage_update: None,
+			changes_trie_config_update: None,
 			_phantom: Default::default(),
 		})
 	}
@@ -148,6 +153,9 @@ impl<S, Block> ClientBackend<Block> for Backend<S, HasherFor<Block>>
 
 		if let Some(header) = operation.header {
 			let is_genesis_import = header.number().is_zero();
+			if let Some(new_config) = operation.changes_trie_config_update {
+				operation.cache.insert(well_known_cache_keys::CHANGES_TRIE_CONFIG, new_config.encode());
+			}
 			self.blockchain.storage().import_header(
 				header,
 				operation.cache,
@@ -194,7 +202,7 @@ impl<S, Block> ClientBackend<Block> for Backend<S, HasherFor<Block>>
 		self.blockchain.storage().usage_info()
 	}
 
-	fn changes_trie_storage(&self) -> Option<&Self::ChangesTrieStorage> {
+	fn changes_trie_storage(&self) -> Option<&dyn PrunableStateChangesTrieStorage<Block>> {
 		None
 	}
 
@@ -296,6 +304,13 @@ impl<S, Block> BlockImportOperation<Block> for ImportOperation<Block, S>
 	fn reset_storage(&mut self, input: Storage) -> ClientResult<Block::Hash> {
 		check_genesis_storage(&input)?;
 
+		// changes trie configuration
+		let changes_trie_config = input.top.iter()
+			.find(|(k, _)| &k[..] == well_known_keys::CHANGES_TRIE_CONFIG)
+			.map(|(_, v)| Decode::decode(&mut &v[..])
+				.expect("changes trie configuration is encoded properly at genesis"));
+		self.changes_trie_config_update = Some(changes_trie_config);
+
 		// this is only called when genesis block is imported => shouldn't be performance bottleneck
 		let mut storage: HashMap<Option<(Vec<u8>, OwnedChildInfo)>, _> = HashMap::new();
 		storage.insert(None, input.top);
diff --git a/client/src/light/call_executor.rs b/client/src/light/call_executor.rs
index 45d9bf303c0cb..01a93c78219bc 100644
--- a/client/src/light/call_executor.rs
+++ b/client/src/light/call_executor.rs
@@ -222,7 +222,7 @@ pub fn check_execution_proof<Header, E, H>(
 ) -> ClientResult<Vec<u8>>
 	where
 		Header: HeaderT,
-		E: CodeExecutor,
+		E: CodeExecutor + Clone + 'static,
 		H: Hasher,
 		H::Out: Ord + codec::Codec + 'static,
 {
@@ -248,7 +248,7 @@ fn check_execution_proof_with_make_header<Header, E, H, MakeNextHeader: Fn(&Head
 ) -> ClientResult<Vec<u8>>
 	where
 		Header: HeaderT,
-		E: CodeExecutor,
+		E: CodeExecutor + Clone + 'static,
 		H: Hasher,
 		H::Out: Ord + codec::Codec + 'static,
 {
@@ -259,7 +259,7 @@ fn check_execution_proof_with_make_header<Header, E, H, MakeNextHeader: Fn(&Head
 	let mut changes = OverlayedChanges::default();
 	let trie_backend = create_proof_check_backend(root, remote_proof)?;
 	let next_header = make_next_header(&request.header);
-	execution_proof_check_on_trie_backend::<H, _>(
+	execution_proof_check_on_trie_backend::<H, Header::Number, _>(
 		&trie_backend,
 		&mut changes,
 		executor,
@@ -268,7 +268,7 @@ fn check_execution_proof_with_make_header<Header, E, H, MakeNextHeader: Fn(&Head
 	)?;
 
 	// execute method
-	execution_proof_check_on_trie_backend::<H, _>(
+	execution_proof_check_on_trie_backend::<H, Header::Number, _>(
 		&trie_backend,
 		&mut changes,
 		executor,
diff --git a/client/src/light/fetcher.rs b/client/src/light/fetcher.rs
index d746b3abe5549..d66108b7f0adb 100644
--- a/client/src/light/fetcher.rs
+++ b/client/src/light/fetcher.rs
@@ -25,12 +25,12 @@ use codec::{Decode, Encode};
 use sp_core::{convert_hash, traits::CodeExecutor};
 use sp_runtime::traits::{
 	Block as BlockT, Header as HeaderT, Hash, HashFor, NumberFor,
-	SimpleArithmetic, CheckedConversion, Zero,
+	SimpleArithmetic, CheckedConversion,
 };
 use sp_state_machine::{
 	ChangesTrieRootsStorage, ChangesTrieAnchorBlockId, ChangesTrieConfigurationRange,
-	TrieBackend, read_proof_check, key_changes_proof_check, create_proof_check_backend_storage,
-	read_child_proof_check,
+	InMemoryChangesTrieStorage, TrieBackend, read_proof_check, key_changes_proof_check_with_db,
+	create_proof_check_backend_storage, read_child_proof_check,
 };
 pub use sp_state_machine::StorageProof;
 use sp_blockchain::{Error as ClientError, Result as ClientResult};
@@ -113,30 +113,34 @@ impl<E, H, B: BlockT, S: BlockchainStorage<B>> LightDataChecker<E, H, B, S> {
 			)?;
 		}
 
-		// FIXME: remove this in https://github.com/paritytech/substrate/pull/3201
-		let changes_trie_config_range = ChangesTrieConfigurationRange {
-			config: &request.changes_trie_config,
-			zero: Zero::zero(),
-			end: None,
-		};
-
 		// and now check the key changes proof + get the changes
-		key_changes_proof_check::<H, _>(
-			changes_trie_config_range,
-			&RootsStorage {
-				roots: (request.tries_roots.0, &request.tries_roots.2),
-				prev_roots: remote_roots,
-			},
-			remote_proof,
-			request.first_block.0,
-			&ChangesTrieAnchorBlockId {
-				hash: convert_hash(&request.last_block.1),
-				number: request.last_block.0,
-			},
-			remote_max_block,
-			request.storage_key.as_ref().map(Vec::as_slice),
-			&request.key)
-		.map_err(|err| ClientError::ChangesTrieAccessFailed(err))
+		let mut result = Vec::new();
+		let proof_storage = InMemoryChangesTrieStorage::with_proof(remote_proof);
+		for config_range in &request.changes_trie_configs {
+			let result_range = key_changes_proof_check_with_db::<H, _>(
+				ChangesTrieConfigurationRange {
+					config: config_range.config.as_ref().ok_or(ClientError::ChangesTriesNotSupported)?,
+					zero: config_range.zero.0,
+					end: config_range.end.map(|(n, _)| n),
+				},
+				&RootsStorage {
+					roots: (request.tries_roots.0, &request.tries_roots.2),
+					prev_roots: &remote_roots,
+				},
+				&proof_storage,
+				request.first_block.0,
+				&ChangesTrieAnchorBlockId {
+					hash: convert_hash(&request.last_block.1),
+					number: request.last_block.0,
+				},
+				remote_max_block,
+				request.storage_key.as_ref().map(Vec::as_slice),
+				&request.key)
+			.map_err(|err| ClientError::ChangesTrieAccessFailed(err))?;
+			result.extend(result_range);
+		}
+
+		Ok(result)
 	}
 
 	/// Check CHT-based proof for changes tries roots.
@@ -197,7 +201,7 @@ impl<E, H, B: BlockT, S: BlockchainStorage<B>> LightDataChecker<E, H, B, S> {
 impl<E, Block, H, S> FetchChecker<Block> for LightDataChecker<E, H, Block, S>
 	where
 		Block: BlockT,
-		E: CodeExecutor,
+		E: CodeExecutor + Clone + 'static,
 		H: Hasher,
 		H::Out: Ord + codec::Codec + 'static,
 		S: BlockchainStorage<Block>,
@@ -284,7 +288,7 @@ impl<E, Block, H, S> FetchChecker<Block> for LightDataChecker<E, H, Block, S>
 /// A view of BTreeMap<Number, Hash> as a changes trie roots storage.
 struct RootsStorage<'a, Number: SimpleArithmetic, Hash: 'a> {
 	roots: (Number, &'a [Hash]),
-	prev_roots: BTreeMap<Number, Hash>,
+	prev_roots: &'a BTreeMap<Number, Hash>,
 }
 
 impl<'a, H, Number, Hash> ChangesTrieRootsStorage<H, Number> for RootsStorage<'a, Number, Hash>
@@ -340,7 +344,7 @@ pub mod tests {
 	use crate::in_mem::{Blockchain as InMemoryBlockchain};
 	use crate::light::fetcher::{FetchChecker, LightDataChecker, RemoteHeaderRequest};
 	use crate::light::blockchain::tests::{DummyStorage, DummyBlockchain};
-	use sp_core::{blake2_256, Blake2Hasher, H256};
+	use sp_core::{blake2_256, Blake2Hasher, ChangesTrieConfiguration, H256};
 	use sp_core::storage::{well_known_keys, StorageKey, ChildInfo};
 	use sp_runtime::generic::BlockId;
 	use sp_state_machine::Backend;
@@ -569,8 +573,13 @@ pub mod tests {
 
 			// check proof on local client
 			let local_roots_range = local_roots.clone()[(begin - 1) as usize..].to_vec();
+			let config = ChangesTrieConfiguration::new(4, 2);
 			let request = RemoteChangesRequest::<Header> {
-				changes_trie_config: runtime::changes_trie_config(),
+				changes_trie_configs: vec![sp_core::ChangesTrieConfigurationRange {
+					zero: (0, Default::default()),
+					end: None,
+					config: Some(config),
+				}],
 				first_block: (begin, begin_hash),
 				last_block: (end, end_hash),
 				max_block: (max, max_hash),
@@ -624,8 +633,13 @@ pub mod tests {
 		);
 
 		// check proof on local client
+		let config = ChangesTrieConfiguration::new(4, 2);
 		let request = RemoteChangesRequest::<Header> {
-			changes_trie_config: runtime::changes_trie_config(),
+			changes_trie_configs: vec![sp_core::ChangesTrieConfigurationRange {
+				zero: (0, Default::default()),
+				end: None,
+				config: Some(config),
+			}],
 			first_block: (1, b1),
 			last_block: (4, b4),
 			max_block: (4, b4),
@@ -665,8 +679,13 @@ pub mod tests {
 			begin_hash, end_hash, begin_hash, max_hash, None, &key).unwrap();
 
 		let local_roots_range = local_roots.clone()[(begin - 1) as usize..].to_vec();
+		let config = ChangesTrieConfiguration::new(4, 2);
 		let request = RemoteChangesRequest::<Header> {
-			changes_trie_config: runtime::changes_trie_config(),
+			changes_trie_configs: vec![sp_core::ChangesTrieConfigurationRange {
+				zero: (0, Default::default()),
+				end: None,
+				config: Some(config),
+			}],
 			first_block: (begin, begin_hash),
 			last_block: (end, end_hash),
 			max_block: (max, max_hash),
diff --git a/client/src/light/mod.rs b/client/src/light/mod.rs
index 5052b36d7f3e1..d65fdef71193d 100644
--- a/client/src/light/mod.rs
+++ b/client/src/light/mod.rs
@@ -56,7 +56,7 @@ pub fn new_light_backend<B, S>(blockchain: Arc<Blockchain<S>>) -> Arc<Backend<S,
 /// Create an instance of light client.
 pub fn new_light<B, S, GS, RA, E>(
 	backend: Arc<Backend<S, HasherFor<B>>>,
-	genesis_storage: GS,
+	genesis_storage: &GS,
 	code_executor: E,
 ) -> ClientResult<
 		Client<
@@ -73,7 +73,7 @@ pub fn new_light<B, S, GS, RA, E>(
 		B: BlockT,
 		S: BlockchainStorage<B> + 'static,
 		GS: BuildStorage,
-		E: CodeExecutor + RuntimeInfo,
+		E: CodeExecutor + RuntimeInfo + Clone + 'static,
 {
 	let local_executor = LocalCallExecutor::new(backend.clone(), code_executor);
 	let executor = GenesisCallExecutor::new(backend.clone(), local_executor);
diff --git a/client/state-db/Cargo.toml b/client/state-db/Cargo.toml
index 31335d752ea67..9e162c5cb9898 100644
--- a/client/state-db/Cargo.toml
+++ b/client/state-db/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "sc-state-db"
-version = "2.0.0"
+version = "0.8.0"
 authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2018"
 
diff --git a/client/tracing/src/lib.rs b/client/tracing/src/lib.rs
index 451f22fe14f6c..b6c1b1120f4ed 100644
--- a/client/tracing/src/lib.rs
+++ b/client/tracing/src/lib.rs
@@ -290,6 +290,6 @@ fn send_telemetry(span_datum: SpanDatum) {
 	);
 }
 
-fn send_prometheus(span_datum: SpanDatum) {
+fn send_prometheus(_span_datum: SpanDatum) {
 	unimplemented!()
 }
diff --git a/client/transaction-pool/graph/src/validated_pool.rs b/client/transaction-pool/graph/src/validated_pool.rs
index 7af32c88184e6..29f82fb894ac0 100644
--- a/client/transaction-pool/graph/src/validated_pool.rs
+++ b/client/transaction-pool/graph/src/validated_pool.rs
@@ -470,12 +470,15 @@ impl<B: ChainApi> ValidatedPool<B> {
 			return vec![]
 		}
 
+		debug!(target: "txpool", "Removing invalid transactions: {:?}", hashes);
+
 		// temporarily ban invalid transactions
-		debug!(target: "txpool", "Banning invalid transactions: {:?}", hashes);
 		self.rotator.ban(&time::Instant::now(), hashes.iter().cloned());
 
 		let invalid = self.pool.write().remove_subtree(hashes);
 
+		debug!(target: "txpool", "Removed invalid transactions: {:?}", invalid);
+
 		let mut listener = self.listener.write();
 		for tx in &invalid {
 			listener.invalid(&tx.hash, true);
diff --git a/docs/CODEOWNERS b/docs/CODEOWNERS
index bc4559805b3e0..9304f278534bb 100644
--- a/docs/CODEOWNERS
+++ b/docs/CODEOWNERS
@@ -46,11 +46,16 @@
 /client/finality-grandpa/ @andresilva @DemiMarie-parity
 /client/consensus/babe/ @andresilva @DemiMarie-parity
 /client/consensus/slots/ @andresilva @DemiMarie-parity
+/client/consensus/pow/ @sorpaas
+/primitives/consensus/pow/ @sorpaas
 
 # Contracts
 /frame/contracts/ @pepyakin @thiolliere
 /frame/contracts/src/wasm/runtime.rs @Robbepop
 
+# EVM
+/frame/evm/ @sorpaas
+
 # Inflation points
 /frame/staking/src/inflation.rs @thiolliere
 
diff --git a/frame/balances/Cargo.toml b/frame/balances/Cargo.toml
index e5a3c4f2d7602..f9522b5379ff5 100644
--- a/frame/balances/Cargo.toml
+++ b/frame/balances/Cargo.toml
@@ -6,7 +6,6 @@ edition = "2018"
 
 [dependencies]
 serde = { version = "1.0.101", optional = true }
-safe-mix = { version = "1.0.0", default-features = false }
 codec = { package = "parity-scale-codec", version = "1.0.0", default-features = false, features = ["derive"] }
 sp-std = { version = "2.0.0", default-features = false, path = "../../primitives/std" }
 sp-runtime = { version = "2.0.0", default-features = false, path = "../../primitives/runtime" }
@@ -22,7 +21,6 @@ pallet-transaction-payment = { version = "2.0.0", path = "../transaction-payment
 default = ["std"]
 std = [
 	"serde",
-	"safe-mix/std",
 	"codec/std",
 	"sp-std/std",
 	"frame-support/std",
diff --git a/frame/balances/src/lib.rs b/frame/balances/src/lib.rs
index 1f8e099880b7d..b488b96701cf1 100644
--- a/frame/balances/src/lib.rs
+++ b/frame/balances/src/lib.rs
@@ -885,7 +885,10 @@ where
 		Self::free_balance(who) + Self::reserved_balance(who)
 	}
 
+	// Check if `value` amount of free balance can be slashed from `who`.
+	// Is a no-op if value to be slashed is zero.
 	fn can_slash(who: &T::AccountId, value: Self::Balance) -> bool {
+		if value.is_zero() { return true }
 		Self::free_balance(who) >= value
 	}
 
@@ -901,7 +904,10 @@ where
 		<FreeBalance<T, I>>::get(who)
 	}
 
+	// Burn funds from the total issuance, returning a positive imbalance for the amount burned.
+	// Is a no-op if amount to be burned is zero.
 	fn burn(mut amount: Self::Balance) -> Self::PositiveImbalance {
+		if amount.is_zero() { return PositiveImbalance::zero() }
 		<TotalIssuance<T, I>>::mutate(|issued| {
 			*issued = issued.checked_sub(&amount).unwrap_or_else(|| {
 				amount = *issued;
@@ -911,7 +917,11 @@ where
 		PositiveImbalance::new(amount)
 	}
 
+	// Create new funds into the total issuance, returning a negative imbalance
+	// for the amount issued.
+	// Is a no-op if amount to be issued it zero.
 	fn issue(mut amount: Self::Balance) -> Self::NegativeImbalance {
+		if amount.is_zero() { return NegativeImbalance::zero() }
 		<TotalIssuance<T, I>>::mutate(|issued|
 			*issued = issued.checked_add(&amount).unwrap_or_else(|| {
 				amount = Self::Balance::max_value() - *issued;
@@ -921,16 +931,21 @@ where
 		NegativeImbalance::new(amount)
 	}
 
+	// Ensure that an account can withdraw from their free balance given any existing withdrawal
+	// restrictions like locks and vesting balance.
+	// Is a no-op if amount to be withdrawn is zero.
+	//
 	// # <weight>
 	// Despite iterating over a list of locks, they are limited by the number of
 	// lock IDs, which means the number of runtime modules that intend to use and create locks.
 	// # </weight>
 	fn ensure_can_withdraw(
 		who: &T::AccountId,
-		_amount: T::Balance,
+		amount: T::Balance,
 		reasons: WithdrawReasons,
 		new_balance: T::Balance,
 	) -> DispatchResult {
+		if amount.is_zero() { return Ok(()) }
 		if reasons.intersects(WithdrawReason::Reserve | WithdrawReason::Transfer)
 			&& Self::vesting_balance(who) > new_balance
 		{
@@ -955,12 +970,15 @@ where
 		}
 	}
 
+	// Transfer some free balance from `transactor` to `dest`, respecting existence requirements.
+	// Is a no-op if value to be transferred is zero.
 	fn transfer(
 		transactor: &T::AccountId,
 		dest: &T::AccountId,
 		value: Self::Balance,
 		existence_requirement: ExistenceRequirement,
 	) -> DispatchResult {
+		if value.is_zero() { return Ok(()) }
 		let from_balance = Self::free_balance(transactor);
 		let to_balance = Self::free_balance(dest);
 		let would_create = to_balance.is_zero();
@@ -1001,12 +1019,16 @@ where
 		Ok(())
 	}
 
+	// Withdraw some free balance from an account, respecting existence requirements.
+	// Is a no-op if value to be withdrawn is zero.
 	fn withdraw(
 		who: &T::AccountId,
 		value: Self::Balance,
 		reasons: WithdrawReasons,
 		liveness: ExistenceRequirement,
 	) -> result::Result<Self::NegativeImbalance, DispatchError> {
+		if value.is_zero() { return Ok(NegativeImbalance::zero()); }
+
 		let old_balance = Self::free_balance(who);
 		if let Some(new_balance) = old_balance.checked_sub(&value) {
 			// if we need to keep the account alive...
@@ -1026,10 +1048,15 @@ where
 		}
 	}
 
+	// Slash an account, returning the negative imbalance created and any left over
+	// amount that could not be slashed.
+	// Is a no-op if value to be slashed is zero.
 	fn slash(
 		who: &T::AccountId,
 		value: Self::Balance
 	) -> (Self::NegativeImbalance, Self::Balance) {
+		if value.is_zero() { return (NegativeImbalance::zero(), Zero::zero()) }
+
 		let free_balance = Self::free_balance(who);
 		let free_slash = cmp::min(free_balance, value);
 
@@ -1049,10 +1076,14 @@ where
 		}
 	}
 
+	// Deposit some `value` into the free balance of an existing account.
+	// Is a no-op if the value to be deposited is zero.
 	fn deposit_into_existing(
 		who: &T::AccountId,
 		value: Self::Balance
 	) -> result::Result<Self::PositiveImbalance, DispatchError> {
+		if value.is_zero() { return Ok(PositiveImbalance::zero()) }
+
 		if Self::total_balance(who).is_zero() {
 			Err(Error::<T, I>::DeadAccount)?
 		}
@@ -1060,10 +1091,14 @@ where
 		Ok(PositiveImbalance::new(value))
 	}
 
+	// Deposit some `value` into the free balance of `who`, possibly creating a new account.
+	// Is a no-op if the value to be deposited is zero.
 	fn deposit_creating(
 		who: &T::AccountId,
 		value: Self::Balance,
 	) -> Self::PositiveImbalance {
+		if value.is_zero() { return Self::PositiveImbalance::zero() }
+
 		let (imbalance, _) = Self::make_free_balance_be(who, Self::free_balance(who) + value);
 		if let SignedImbalance::Positive(p) = imbalance {
 			p
@@ -1122,7 +1157,10 @@ impl<T: Trait<I>, I: Instance> ReservableCurrency<T::AccountId> for Module<T, I>
 where
 	T::Balance: MaybeSerializeDeserialize + Debug
 {
+	// Check if `who` can reserve `value` from their free balance.
+	// Is a no-op if value to be reserved is zero.
 	fn can_reserve(who: &T::AccountId, value: Self::Balance) -> bool {
+		if value.is_zero() { return true }
 		Self::free_balance(who)
 			.checked_sub(&value)
 			.map_or(false, |new_balance|
@@ -1134,7 +1172,10 @@ where
 		<ReservedBalance<T, I>>::get(who)
 	}
 
+	// Move `value` from the free balance from `who` to their reserved balance.
+	// Is a no-op if value to be reserved is zero.
 	fn reserve(who: &T::AccountId, value: Self::Balance) -> result::Result<(), DispatchError> {
+		if value.is_zero() { return Ok(()) }
 		let b = Self::free_balance(who);
 		if b < value {
 			Err(Error::<T, I>::InsufficientBalance)?
@@ -1146,7 +1187,10 @@ where
 		Ok(())
 	}
 
+	// Unreserve some funds, returning any amount that was unable to be unreserved.
+	// Is a no-op if the value to be unreserved is zero.
 	fn unreserve(who: &T::AccountId, value: Self::Balance) -> Self::Balance {
+		if value.is_zero() { return Zero::zero() }
 		let b = Self::reserved_balance(who);
 		let actual = cmp::min(b, value);
 		Self::set_free_balance(who, Self::free_balance(who) + actual);
@@ -1154,10 +1198,14 @@ where
 		value - actual
 	}
 
+	// Slash from reserved balance, returning the negative imbalance created,
+	// and any amount that was unable to be slashed.
+	// Is a no-op if the value to be slashed is zero.
 	fn slash_reserved(
 		who: &T::AccountId,
 		value: Self::Balance
 	) -> (Self::NegativeImbalance, Self::Balance) {
+		if value.is_zero() { return (NegativeImbalance::zero(), Zero::zero()) }
 		let b = Self::reserved_balance(who);
 		let slash = cmp::min(b, value);
 		// underflow should never happen, but it if does, there's nothing to be done here.
@@ -1165,11 +1213,14 @@ where
 		(NegativeImbalance::new(slash), value - slash)
 	}
 
+	// Move the reserved balance of one account into the free balance of another.
+	// Is a no-op if the value to be moved is zero.
 	fn repatriate_reserved(
 		slashed: &T::AccountId,
 		beneficiary: &T::AccountId,
 		value: Self::Balance,
 	) -> result::Result<Self::Balance, DispatchError> {
+		if value.is_zero() { return Ok (Zero::zero()) }
 		if Self::total_balance(beneficiary).is_zero() {
 			Err(Error::<T, I>::DeadAccount)?
 		}
@@ -1187,6 +1238,8 @@ where
 {
 	type Moment = T::BlockNumber;
 
+	// Set a lock on the balance of `who`.
+	// Is a no-op if lock amount is zero.
 	fn set_lock(
 		id: LockIdentifier,
 		who: &T::AccountId,
@@ -1194,6 +1247,7 @@ where
 		until: T::BlockNumber,
 		reasons: WithdrawReasons,
 	) {
+		if amount.is_zero() { return }
 		let now = <frame_system::Module<T>>::block_number();
 		let mut new_lock = Some(BalanceLock { id, amount, until, reasons });
 		let mut locks = Self::locks(who).into_iter().filter_map(|l|
@@ -1275,12 +1329,14 @@ where
 	///
 	/// If there already exists a vesting schedule for the given account, an `Err` is returned
 	/// and nothing is updated.
+	/// Is a no-op if the amount to be vested is zero.
 	fn add_vesting_schedule(
 		who: &T::AccountId,
 		locked: T::Balance,
 		per_block: T::Balance,
 		starting_block: T::BlockNumber
 	) -> DispatchResult {
+		if locked.is_zero() { return Ok(()) }
 		if <Vesting<T, I>>::exists(who) {
 			Err(Error::<T, I>::ExistingVestingSchedule)?
 		}
diff --git a/frame/collective/Cargo.toml b/frame/collective/Cargo.toml
index 6bf3c1b9b5c78..a2150b82dd5e6 100644
--- a/frame/collective/Cargo.toml
+++ b/frame/collective/Cargo.toml
@@ -6,7 +6,6 @@ edition = "2018"
 
 [dependencies]
 serde = { version = "1.0.101", optional = true }
-safe-mix = { version = "1.0.0", default-features = false }
 codec = { package = "parity-scale-codec", version = "1.0.0", default-features = false, features = ["derive"] }
 sp-core = { version = "2.0.0", default-features = false, path = "../../primitives/core" }
 sp-std = { version = "2.0.0", default-features = false, path = "../../primitives/std" }
@@ -22,7 +21,6 @@ pallet-balances = { version = "2.0.0", path = "../balances" }
 [features]
 default = ["std"]
 std = [
-	"safe-mix/std",
 	"codec/std",
 	"sp-core/std",
 	"sp-std/std",
diff --git a/frame/contracts/Cargo.toml b/frame/contracts/Cargo.toml
index c6102d23eabbe..d583809f0bfa7 100644
--- a/frame/contracts/Cargo.toml
+++ b/frame/contracts/Cargo.toml
@@ -14,7 +14,7 @@ sp-core = { version = "2.0.0", default-features = false, path = "../../primitive
 sp-runtime = { version = "2.0.0", default-features = false, path = "../../primitives/runtime" }
 sp-io = { version = "2.0.0", default-features = false, path = "../../primitives/io" }
 sp-std = { version = "2.0.0", default-features = false, path = "../../primitives/std" }
-sp-sandbox = { version = "2.0.0", default-features = false, path = "../../primitives/sandbox" }
+sp-sandbox = { version = "0.8.0", default-features = false, path = "../../primitives/sandbox" }
 frame-support = { version = "2.0.0", default-features = false, path = "../support" }
 frame-system = { version = "2.0.0", default-features = false, path = "../system" }
 
diff --git a/frame/contracts/rpc/Cargo.toml b/frame/contracts/rpc/Cargo.toml
index c563d9f727dec..61eb55368eb10 100644
--- a/frame/contracts/rpc/Cargo.toml
+++ b/frame/contracts/rpc/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "pallet-contracts-rpc"
-version = "2.0.0"
+version = "0.8.0"
 authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2018"
 
@@ -15,7 +15,7 @@ sp-rpc = { version = "2.0.0", path = "../../../primitives/rpc" }
 serde = { version = "1.0.101", features = ["derive"] }
 sp-runtime = { version = "2.0.0", path = "../../../primitives/runtime" }
 sp-api = { version = "2.0.0", path = "../../../primitives/api" }
-pallet-contracts-rpc-runtime-api = { version = "2.0.0", path = "./runtime-api" }
+pallet-contracts-rpc-runtime-api = { version = "0.8.0", path = "./runtime-api" }
 
 [dev-dependencies]
 serde_json = "1.0.41"
diff --git a/frame/contracts/rpc/runtime-api/Cargo.toml b/frame/contracts/rpc/runtime-api/Cargo.toml
index c8e183237cf43..e0cbd73f807f2 100644
--- a/frame/contracts/rpc/runtime-api/Cargo.toml
+++ b/frame/contracts/rpc/runtime-api/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "pallet-contracts-rpc-runtime-api"
-version = "2.0.0"
+version = "0.8.0"
 authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2018"
 
diff --git a/frame/democracy/Cargo.toml b/frame/democracy/Cargo.toml
index 8e1aa13fc67f9..02145e8589bab 100644
--- a/frame/democracy/Cargo.toml
+++ b/frame/democracy/Cargo.toml
@@ -6,7 +6,6 @@ edition = "2018"
 
 [dependencies]
 serde = { version = "1.0.101", optional = true, features = ["derive"] }
-safe-mix = { version = "1.0.0", default-features = false }
 codec = { package = "parity-scale-codec", version = "1.0.0", default-features = false, features = ["derive"] }
 sp-std = { version = "2.0.0", default-features = false, path = "../../primitives/std" }
 sp-io = { version = "2.0.0", default-features = false, path = "../../primitives/io" }
@@ -22,7 +21,6 @@ pallet-balances = { version = "2.0.0", path = "../balances" }
 default = ["std"]
 std = [
 	"serde",
-	"safe-mix/std",
 	"codec/std",
 	"sp-std/std",
 	"sp-io/std",
diff --git a/frame/democracy/src/lib.rs b/frame/democracy/src/lib.rs
index 354e93cc292ee..d7790be8f7065 100644
--- a/frame/democracy/src/lib.rs
+++ b/frame/democracy/src/lib.rs
@@ -497,7 +497,7 @@ decl_module! {
 		}
 
 		/// Vote in a referendum on behalf of a stash. If `vote.is_aye()`, the vote is to enact
-		/// the proposal;  otherwise it is a vote to keep the status quo.
+		/// the proposal; otherwise it is a vote to keep the status quo.
 		///
 		/// # <weight>
 		/// - O(1).
diff --git a/frame/elections/Cargo.toml b/frame/elections/Cargo.toml
index 44d624b986240..495151018e7d8 100644
--- a/frame/elections/Cargo.toml
+++ b/frame/elections/Cargo.toml
@@ -6,7 +6,6 @@ edition = "2018"
 
 [dependencies]
 serde = { version = "1.0.101", optional = true }
-safe-mix = { version = "1.0.0", default-features = false }
 codec = { package = "parity-scale-codec", version = "1.0.0", default-features = false, features = ["derive"] }
 sp-core = { version = "2.0.0", default-features = false, path = "../../primitives/core" }
 sp-std = { version = "2.0.0", default-features = false, path = "../../primitives/std" }
@@ -22,7 +21,6 @@ pallet-balances = { version = "2.0.0", path = "../balances" }
 [features]
 default = ["std"]
 std = [
-	"safe-mix/std",
 	"codec/std",
 	"sp-core/std",
 	"sp-std/std",
diff --git a/frame/generic-asset/src/lib.rs b/frame/generic-asset/src/lib.rs
index 0a0209b20f175..3b509a683d705 100644
--- a/frame/generic-asset/src/lib.rs
+++ b/frame/generic-asset/src/lib.rs
@@ -95,9 +95,10 @@
 //! This will emit the `Transferred` event.
 //! - `reserve`: Moves an amount from free balance to reserved balance.
 //! - `unreserve`: Move up to an amount from reserved balance to free balance. This function cannot fail.
+//! - `mint_free`: Mint to an account's free balance.
+//! - `burn_free`: Burn an account's free balance.
 //! - `slash`: Deduct up to an amount from the combined balance of `who`, preferring to deduct from the
 //!	free balance. This function cannot fail.
-//! - `reward`: Add up to an amount to the free balance of an account.
 //! - `slash_reserved`: Deduct up to an amount from reserved balance of an account. This function cannot fail.
 //! - `repatriate_reserved`: Move up to an amount from reserved balance of an account to free balance of another
 //! account.
@@ -109,7 +110,7 @@
 //!
 //! The following examples show how to use the Generic Asset module in your custom module.
 //!
-//! ### Examples from the PRML
+//! ### Examples from the frame module
 //!
 //! The Fees module uses the `Currency` trait to handle fee charge/refund, and its types inherit from `Currency`:
 //!
@@ -162,7 +163,7 @@ use sp_runtime::traits::{
 use sp_std::prelude::*;
 use sp_std::{cmp, result, fmt::Debug};
 use frame_support::{
-	decl_event, decl_module, decl_storage, ensure, dispatch, decl_error,
+	decl_event, decl_module, decl_storage, ensure, decl_error,
 	traits::{
 		Currency, ExistenceRequirement, Imbalance, LockIdentifier, LockableCurrency, ReservableCurrency,
 		SignedImbalance, UpdateBalanceOutcome, WithdrawReason, WithdrawReasons, TryDrop,
@@ -359,7 +360,7 @@ decl_module! {
 		fn deposit_event() = default;
 
 		/// Create a new kind of asset.
-		fn create(origin, options: AssetOptions<T::Balance, T::AccountId>) -> dispatch::DispatchResult {
+		fn create(origin, options: AssetOptions<T::Balance, T::AccountId>) -> DispatchResult {
 			let origin = ensure_signed(origin)?;
 			let id = Self::next_asset_id();
 
@@ -392,7 +393,7 @@ decl_module! {
 			origin,
 			#[compact] asset_id: T::AssetId,
 			new_permission: PermissionLatest<T::AccountId>
-		) -> dispatch::DispatchResult {
+		) -> DispatchResult {
 			let origin = ensure_signed(origin)?;
 
 			let permissions: PermissionVersions<T::AccountId> = new_permission.into();
@@ -410,56 +411,20 @@ decl_module! {
 
 		/// Mints an asset, increases its total issuance.
 		/// The origin must have `mint` permissions.
-		fn mint(origin, #[compact] asset_id: T::AssetId, to: T::AccountId, amount: T::Balance)
-			-> dispatch::DispatchResult
-		{
-			let origin = ensure_signed(origin)?;
-			if Self::check_permission(&asset_id, &origin, &PermissionType::Mint) {
-				let original_free_balance = Self::free_balance(&asset_id, &to);
-				let current_total_issuance = <TotalIssuance<T>>::get(asset_id);
-				let new_total_issuance = current_total_issuance.checked_add(&amount)
-					.ok_or(Error::<T>::TotalMintingOverflow)?;
-				let value = original_free_balance.checked_add(&amount)
-					.ok_or(Error::<T>::FreeMintingOverflow)?;
-
-				<TotalIssuance<T>>::insert(asset_id, new_total_issuance);
-				Self::set_free_balance(&asset_id, &to, value);
-
-				Self::deposit_event(RawEvent::Minted(asset_id, to, amount));
-
-				Ok(())
-			} else {
-				Err(Error::<T>::NoMintPermission)?
-			}
+		fn mint(origin, #[compact] asset_id: T::AssetId, to: T::AccountId, amount: T::Balance) -> DispatchResult {
+			let who = ensure_signed(origin)?;
+			Self::mint_free(&asset_id, &who, &to, &amount)?;
+			Self::deposit_event(RawEvent::Minted(asset_id, to, amount));
+			Ok(())
 		}
 
 		/// Burns an asset, decreases its total issuance.
-		///
 		/// The `origin` must have `burn` permissions.
-		fn burn(origin, #[compact] asset_id: T::AssetId, to: T::AccountId, amount: T::Balance)
-			-> dispatch::DispatchResult
-		{
-			let origin = ensure_signed(origin)?;
-
-			if Self::check_permission(&asset_id, &origin, &PermissionType::Burn) {
-				let original_free_balance = Self::free_balance(&asset_id, &to);
-
-				let current_total_issuance = <TotalIssuance<T>>::get(asset_id);
-				let new_total_issuance = current_total_issuance.checked_sub(&amount)
-					.ok_or(Error::<T>::TotalBurningUnderflow)?;
-				let value = original_free_balance.checked_sub(&amount)
-					.ok_or(Error::<T>::FreeBurningUnderflow)?;
-
-				<TotalIssuance<T>>::insert(asset_id, new_total_issuance);
-
-				Self::set_free_balance(&asset_id, &to, value);
-
-				Self::deposit_event(RawEvent::Burned(asset_id, to, amount));
-
-				Ok(())
-			} else {
-				Err(Error::<T>::NoBurnPermission)?
-			}
+		fn burn(origin, #[compact] asset_id: T::AssetId, to: T::AccountId, amount: T::Balance) -> DispatchResult {
+			let who = ensure_signed(origin)?;
+			Self::burn_free(&asset_id, &who, &to, &amount)?;
+			Self::deposit_event(RawEvent::Burned(asset_id, to, amount));
+			Ok(())
 		}
 
 		/// Can be used to create reserved tokens.
@@ -468,7 +433,7 @@ decl_module! {
 			origin,
 			asset_id: T::AssetId,
 			options: AssetOptions<T::Balance, T::AccountId>
-		) -> dispatch::DispatchResult {
+		) -> DispatchResult {
 			ensure_root(origin)?;
 			Self::create_asset(Some(asset_id), None, options)
 		}
@@ -565,6 +530,53 @@ impl<T: Trait> Module<T> {
 		<ReservedBalance<T>>::get(asset_id, who)
 	}
 
+	/// Mint to an account's free balance, without event
+	pub fn mint_free(
+		asset_id: &T::AssetId,
+		who: &T::AccountId,
+		to: &T::AccountId,
+		amount: &T::Balance,
+	) -> DispatchResult {
+		if Self::check_permission(asset_id, who, &PermissionType::Mint) {
+			let original_free_balance = Self::free_balance(&asset_id, &to);
+			let current_total_issuance = <TotalIssuance<T>>::get(asset_id);
+			let new_total_issuance = current_total_issuance.checked_add(&amount)
+				.ok_or(Error::<T>::TotalMintingOverflow)?;
+			let value = original_free_balance.checked_add(&amount)
+				.ok_or(Error::<T>::FreeMintingOverflow)?;
+
+			<TotalIssuance<T>>::insert(asset_id, new_total_issuance);
+			Self::set_free_balance(&asset_id, &to, value);
+			Ok(())
+		} else {
+			Err(Error::<T>::NoMintPermission)?
+		}
+	}
+
+	/// Burn an account's free balance, without event
+	pub fn burn_free(
+		asset_id: &T::AssetId,
+		who: &T::AccountId,
+		to: &T::AccountId,
+		amount: &T::Balance,
+	) -> DispatchResult {
+		if Self::check_permission(asset_id, who, &PermissionType::Burn) {
+			let original_free_balance = Self::free_balance(asset_id, to);
+
+			let current_total_issuance = <TotalIssuance<T>>::get(asset_id);
+			let new_total_issuance = current_total_issuance.checked_sub(amount)
+				.ok_or(Error::<T>::TotalBurningUnderflow)?;
+			let value = original_free_balance.checked_sub(amount)
+				.ok_or(Error::<T>::FreeBurningUnderflow)?;
+
+			<TotalIssuance<T>>::insert(asset_id, new_total_issuance);
+			Self::set_free_balance(asset_id, to, value);
+			Ok(())
+		} else {
+			Err(Error::<T>::NoBurnPermission)?
+		}
+	}
+
 	/// Creates an asset.
 	///
 	/// # Arguments
@@ -577,7 +589,7 @@ impl<T: Trait> Module<T> {
 		asset_id: Option<T::AssetId>,
 		from_account: Option<T::AccountId>,
 		options: AssetOptions<T::Balance, T::AccountId>,
-	) -> dispatch::DispatchResult {
+	) -> DispatchResult {
 		let asset_id = if let Some(asset_id) = asset_id {
 			ensure!(!<TotalIssuance<T>>::exists(&asset_id), Error::<T>::IdAlreadyTaken);
 			ensure!(asset_id < Self::next_asset_id(), Error::<T>::IdUnavailable);
@@ -610,7 +622,7 @@ impl<T: Trait> Module<T> {
 		from: &T::AccountId,
 		to: &T::AccountId,
 		amount: T::Balance
-	) -> dispatch::DispatchResult {
+	) -> DispatchResult {
 		let new_balance = Self::free_balance(asset_id, from)
 			.checked_sub(&amount)
 			.ok_or(Error::<T>::InsufficientBalance)?;
@@ -631,7 +643,7 @@ impl<T: Trait> Module<T> {
 		from: &T::AccountId,
 		to: &T::AccountId,
 		amount: T::Balance,
-	) -> dispatch::DispatchResult {
+	) -> DispatchResult {
 		Self::make_transfer(asset_id, from, to, amount)?;
 
 		if from != to {
@@ -646,7 +658,7 @@ impl<T: Trait> Module<T> {
 	/// If the free balance is lower than `amount`, then no funds will be moved and an `Err` will
 	/// be returned. This is different behavior than `unreserve`.
 	pub fn reserve(asset_id: &T::AssetId, who: &T::AccountId, amount: T::Balance)
-		-> dispatch::DispatchResult
+		-> DispatchResult
 	{
 		// Do we need to consider that this is an atomic transaction?
 		let original_reserve_balance = Self::reserved_balance(asset_id, who);
@@ -683,7 +695,7 @@ impl<T: Trait> Module<T> {
 	/// then `Some(remaining)` will be returned. Full completion is given by `None`.
 	/// NOTE: LOW-LEVEL: This will not attempt to maintain total issuance. It is expected that
 	/// the caller will do this.
-	fn slash(asset_id: &T::AssetId, who: &T::AccountId, amount: T::Balance) -> Option<T::Balance> {
+	pub fn slash(asset_id: &T::AssetId, who: &T::AccountId, amount: T::Balance) -> Option<T::Balance> {
 		let free_balance = Self::free_balance(asset_id, who);
 		let free_slash = sp_std::cmp::min(free_balance, amount);
 		let new_free_balance = free_balance - free_slash;
@@ -701,7 +713,7 @@ impl<T: Trait> Module<T> {
 	/// is less than `amount`, then a non-zero second item will be returned.
 	/// NOTE: LOW-LEVEL: This will not attempt to maintain total issuance. It is expected that
 	/// the caller will do this.
-	fn slash_reserved(asset_id: &T::AssetId, who: &T::AccountId, amount: T::Balance) -> Option<T::Balance> {
+	pub fn slash_reserved(asset_id: &T::AssetId, who: &T::AccountId, amount: T::Balance) -> Option<T::Balance> {
 		let original_reserve_balance = Self::reserved_balance(asset_id, who);
 		let slash = sp_std::cmp::min(original_reserve_balance, amount);
 		let new_reserve_balance = original_reserve_balance - slash;
@@ -720,7 +732,7 @@ impl<T: Trait> Module<T> {
 	/// the `remaining` would be returned, else `Zero::zero()`.
 	/// NOTE: LOW-LEVEL: This will not attempt to maintain total issuance. It is expected that
 	/// the caller will do this.
-	fn repatriate_reserved(
+	pub fn repatriate_reserved(
 		asset_id: &T::AssetId,
 		who: &T::AccountId,
 		beneficiary: &T::AccountId,
@@ -785,7 +797,7 @@ impl<T: Trait> Module<T> {
 		_amount: T::Balance,
 		reasons: WithdrawReasons,
 		new_balance: T::Balance,
-	) -> dispatch::DispatchResult {
+	) -> DispatchResult {
 		if asset_id != &Self::staking_asset_id() {
 			return Ok(());
 		}
diff --git a/frame/indices/Cargo.toml b/frame/indices/Cargo.toml
index d05a7654d1240..bd83761ff1a25 100644
--- a/frame/indices/Cargo.toml
+++ b/frame/indices/Cargo.toml
@@ -6,7 +6,6 @@ edition = "2018"
 
 [dependencies]
 serde = { version = "1.0.101", optional = true }
-safe-mix = { version = "1.0.0", default-features = false }
 codec = { package = "parity-scale-codec", version = "1.0.0", default-features = false, features = ["derive"] }
 sp-keyring = { version = "2.0.0", optional = true, path = "../../primitives/keyring" }
 sp-std = { version = "2.0.0", default-features = false, path = "../../primitives/std" }
@@ -20,7 +19,6 @@ frame-system = { version = "2.0.0", default-features = false, path = "../system"
 default = ["std"]
 std = [
 	"serde",
-	"safe-mix/std",
 	"sp-keyring",
 	"codec/std",
 	"sp-core/std",
diff --git a/frame/metadata/Cargo.toml b/frame/metadata/Cargo.toml
index 64cf326ff68dc..bcb90d2368928 100644
--- a/frame/metadata/Cargo.toml
+++ b/frame/metadata/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "frame-metadata"
-version = "2.0.0"
+version = "10.0.0"
 authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2018"
 
diff --git a/frame/session/Cargo.toml b/frame/session/Cargo.toml
index 82047dbd68336..aa9aaa1f4479a 100644
--- a/frame/session/Cargo.toml
+++ b/frame/session/Cargo.toml
@@ -6,7 +6,6 @@ edition =  "2018"
 
 [dependencies]
 serde = { version = "1.0.101", optional = true }
-safe-mix = { version = "1.0.0", default-features = false }
 codec = { package = "parity-scale-codec", version = "1.0.0", default-features = false, features = ["derive"] }
 sp-std = { version = "2.0.0", default-features = false, path = "../../primitives/std" }
 sp-runtime = { version = "2.0.0", default-features = false, path = "../../primitives/runtime" }
@@ -28,7 +27,6 @@ default = ["std", "historical"]
 historical = ["sp-trie"]
 std = [
 	"serde",
-	"safe-mix/std",
 	"codec/std",
 	"sp-std/std",
 	"frame-support/std",
diff --git a/frame/society/src/lib.rs b/frame/society/src/lib.rs
index 27051e4caf8d3..f4e5904ea42d7 100644
--- a/frame/society/src/lib.rs
+++ b/frame/society/src/lib.rs
@@ -15,17 +15,17 @@
 // along with Substrate.  If not, see <http://www.gnu.org/licenses/>.
 
 //! # Society Module
-//! 
+//!
 //! - [`society::Trait`](./trait.Trait.html)
 //! - [`Call`](./enum.Call.html)
-//! 
+//!
 //! ## Overview
-//! 
+//!
 //! The Society module is an economic game which incentivizes users to participate
-//! and maintain a membership society. 
-//! 
+//! and maintain a membership society.
+//!
 //! ### User Types
-//! 
+//!
 //! At any point, a user in the society can be one of a:
 //! * Bidder - A user who has submitted intention of joining the society.
 //! * Candidate - A user who will be voted on to join the society.
@@ -33,31 +33,31 @@
 //! * Member - A user who is a member of the society.
 //! * Suspended Member - A member of the society who has accumulated too many strikes
 //! or failed their membership challenge.
-//! 
+//!
 //! Of the non-suspended members, there is always a:
 //! * Head - A member who is exempt from suspension.
 //! * Defender - A member whose membership is under question and voted on again.
-//! 
+//!
 //! Of the non-suspended members of the society, a random set of them are chosen as
 //! "skeptics". The mechanics of skeptics is explained in the
 //! [member phase](#member-phase) below.
-//! 
+//!
 //! ### Mechanics
-//! 
+//!
 //! #### Rewards
-//! 
+//!
 //! Members are incentivized to participate in the society through rewards paid
 //! by the Society treasury. These payments have a maturity period that the user
 //! must wait before they are able to access the funds.
-//! 
+//!
 //! #### Punishments
-//! 
+//!
 //! Members can be punished by slashing the reward payouts that have not been
 //! collected. Additionally, members can accumulate "strikes", and when they
 //! reach a max strike limit, they become suspended.
-//! 
+//!
 //! #### Skeptics
-//! 
+//!
 //! During the voting period, a random set of members are selected as "skeptics".
 //! These skeptics are expected to vote on the current candidates. If they do not vote,
 //! their skeptic status is treated as a rejection vote, the member is deemed
@@ -72,7 +72,7 @@
 //! assuming no one else votes, the defender always get a free vote on their
 //! own challenge keeping them in the society. The Head member is exempt from the
 //! negative outcome of a membership challenge.
-//! 
+//!
 //! #### Society Treasury
 //!
 //! The membership society is independently funded by a treasury managed by this
@@ -80,17 +80,17 @@
 //! to determine the number of accepted bids.
 //!
 //! #### Rate of Growth
-//! 
+//!
 //! The membership society can grow at a rate of 10 accepted candidates per rotation period up
 //! to the max membership threshold. Once this threshold is met, candidate selections
 //! are stalled until there is space for new members to join. This can be resolved by
 //! voting out existing members through the random challenges or by using governance
 //! to increase the maximum membership count.
-//! 
+//!
 //! ### User Life Cycle
-//! 
+//!
 //! A user can go through the following phases:
-//! 
+//!
 //! ```ignore
 //!           +------->  User  <----------+
 //!           |           +               |
@@ -115,40 +115,40 @@
 //! |                                              |
 //! +------------------Society---------------------+
 //! ```
-//! 
+//!
 //! #### Initialization
-//! 
+//!
 //! The society is initialized with a single member who is automatically chosen as the Head.
-//! 
+//!
 //! #### Bid Phase
-//! 
+//!
 //! New users must have a bid to join the society.
-//! 
+//!
 //! A user can make a bid by reserving a deposit. Alternatively, an already existing member
 //! can create a bid on a user's behalf by "vouching" for them.
-//! 
+//!
 //! A bid includes reward information that the user would like to receive for joining
 //! the society. A vouching bid can additionally request some portion of that reward as a tip
 //! to the voucher for vouching for the prospective candidate.
-//! 
+//!
 //! Every rotation period, Bids are ordered by reward amount, and the module
 //! selects as many bids the Society Pot can support for that period.
-//! 
+//!
 //! These selected bids become candidates and move on to the Candidate phase.
 //! Bids that were not selected stay in the bidder pool until they are selected or
 //! a user chooses to "unbid".
-//! 
+//!
 //! #### Candidate Phase
-//! 
+//!
 //! Once a bidder becomes a candidate, members vote whether to approve or reject
 //! that candidate into society. This voting process also happens during a rotation period.
-//! 
+//!
 //! The approval and rejection criteria for candidates are not set on chain,
 //! and may change for different societies.
-//! 
+//!
 //! At the end of the rotation period, we collect the votes for a candidate
 //! and randomly select a vote as the final outcome.
-//! 
+//!
 //! ```ignore
 //!  [ a-accept, r-reject, s-skeptic ]
 //! +----------------------------------+
@@ -163,63 +163,63 @@
 //!
 //! Result: Rejected
 //! ```
-//! 
+//!
 //! Each member that voted opposite to this randomly selected vote is punished by
 //! slashing their unclaimed payouts and increasing the number of strikes they have.
-//! 
+//!
 //! These slashed funds are given to a random user who voted the same as the
 //! selected vote as a reward for participating in the vote.
-//! 
+//!
 //! If the candidate wins the vote, they receive their bid reward as a future payout.
 //! If the bid was placed by a voucher, they will receive their portion of the reward,
 //! before the rest is paid to the winning candidate.
 //!
 //! One winning candidate is selected as the Head of the members. This is randomly
 //! chosen, weighted by the number of approvals the winning candidates accumulated.
-//! 
+//!
 //! If the candidate loses the vote, they are suspended and it is up to the Suspension
 //! Judgement origin to determine if the candidate should go through the bidding process
 //! again, should be accepted into the membership society, or rejected and their deposit
 //! slashed.
-//! 
+//!
 //! #### Member Phase
-//! 
+//!
 //! Once a candidate becomes a member, their role is to participate in society.
-//! 
+//!
 //! Regular participation involves voting on candidates who want to join the membership
 //! society, and by voting in the right way, a member will accumulate future payouts.
 //! When a payout matures, members are able to claim those payouts.
-//! 
+//!
 //! Members can also vouch for users to join the society, and request a "tip" from
 //! the fees the new member would collect by joining the society. This vouching
 //! process is useful in situations where a user may not have enough balance to
 //! satisfy the bid deposit. A member can only vouch one user at a time.
-//! 
+//!
 //! During rotation periods, a random group of members are selected as "skeptics".
 //! These skeptics are expected to vote on the current candidates. If they do not vote,
 //! their skeptic status is treated as a rejection vote, the member is deemed
 //! "lazy", and are given a strike per missing vote.
-//! 
+//!
 //! There is a challenge period in parallel to the rotation period. During a challenge period,
 //! a random member is selected to defend their membership to the society. Other members
 //! make a traditional majority-wins vote to determine if the member should stay in the society.
 //! Ties are treated as a failure of the challenge.
-//! 
+//!
 //! If a member accumulates too many strikes or fails their membership challenge,
 //! they will become suspended. While a member is suspended, they are unable to
 //! claim matured payouts. It is up to the Suspension Judgement origin to determine
 //! if the member should re-enter society or be removed from society with all their
 //! future payouts slashed.
-//! 
+//!
 //! ## Interface
-//! 
+//!
 //! ### Dispatchable Functions
-//! 
+//!
 //! #### For General Users
-//! 
+//!
 //! * `bid` - A user can make a bid to join the membership society by reserving a deposit.
 //! * `unbid` - A user can withdraw their bid for entry, the deposit is returned.
-//! 
+//!
 //! #### For Members
 //!
 //! * `vouch` - A member can place a bid on behalf of a user to join the membership society.
@@ -228,9 +228,10 @@
 //! * `defender_vote` - A member can vote to approve or reject a defender's continued membership
 //! to the society.
 //! * `payout` - A member can claim their first matured payment.
-//! 
+//! * `unfound` - Allow the founder to unfound the society when they are the only member.
+//!
 //! #### For Super Users
-//! 
+//!
 //! * `found` - The founder origin can initiate this society. Useful for bootstrapping the Society
 //! pallet on an already running chain.
 //! * `judge_suspended_member` - The suspension judgement origin is able to make
@@ -254,7 +255,7 @@ use sp_std::prelude::*;
 use codec::{Encode, Decode};
 use sp_runtime::{Percent, ModuleId, RuntimeDebug,
 	traits::{
-		StaticLookup, AccountIdConversion, Saturating, Zero, IntegerSquareRoot,
+		StaticLookup, AccountIdConversion, Saturating, Zero, IntegerSquareRoot, Hash,
 		TrailingZeroInput, CheckedSub, EnsureOrigin
 	}
 };
@@ -305,7 +306,7 @@ pub trait Trait<I=DefaultInstance>: system::Trait {
 	type MaxLockDuration: Get<Self::BlockNumber>;
 
 	/// The origin that is allowed to call `found`.
-	type FounderOrigin: EnsureOrigin<Self::Origin>;
+	type FounderSetOrigin: EnsureOrigin<Self::Origin>;
 
 	/// The origin that is allowed to make suspension judgements.
 	type SuspensionJudgementOrigin: EnsureOrigin<Self::Origin>;
@@ -400,6 +401,14 @@ impl<AccountId: PartialEq, Balance> BidKind<AccountId, Balance> {
 // This module's storage items.
 decl_storage! {
 	trait Store for Module<T: Trait<I>, I: Instance=DefaultInstance> as Society {
+		/// The first member.
+		pub Founder get(founder) build(|config: &GenesisConfig<T, I>| config.members.first().cloned()):
+			Option<T::AccountId>;
+
+		/// A hash of the rules of this society concerning membership. Can only be set once and
+		/// only by the founder.
+		pub Rules get(rules): Option<T::Hash>;
+
 		/// The current set of candidates; bidders that are attempting to become members.
 		pub Candidates get(candidates): Vec<Bid<T::AccountId, BalanceOf<T, I>>>;
 
@@ -422,7 +431,7 @@ decl_storage! {
 		}): Vec<T::AccountId>;
 
 		/// The set of suspended members.
-		pub SuspendedMembers get(fn suspended_member): map T::AccountId => Option<()>;
+		pub SuspendedMembers get(fn suspended_member): map T::AccountId => bool;
 
 		/// The current bids, stored ordered by the value of the bid.
 		Bids: Vec<Bid<T::AccountId, BalanceOf<T, I>>>;
@@ -444,7 +453,7 @@ decl_storage! {
 
 		/// The defending member currently being challenged.
 		Defender get(fn defender): Option<T::AccountId>;
-		
+
 		/// Votes for the defender.
 		DefenderVotes: map hasher(twox_64_concat) T::AccountId => Option<Vote>;
 
@@ -796,28 +805,62 @@ decl_module! {
 		/// This is done as a discrete action in order to allow for the
 		/// module to be included into a running chain and can only be done once.
 		///
-		/// The dispatch origin for this call must be from the _FounderOrigin_.
+		/// The dispatch origin for this call must be from the _FounderSetOrigin_.
 		///
 		/// Parameters:
 		/// - `founder` - The first member and head of the newly founded society.
+		/// - `max_members` - The initial max number of members for the society.
+		/// - `rules` - The rules of this society concerning membership.
 		///
 		/// # <weight>
-		/// - One storage read to check `Head`. O(1)
+		/// - Two storage mutates to set `Head` and `Founder`. O(1)
 		/// - One storage write to add the first member to society. O(1)
-		/// - One storage write to add new Head. O(1)
 		/// - One event.
 		///
 		/// Total Complexity: O(1)
 		/// # </weight>
 		#[weight = SimpleDispatchInfo::FixedNormal(10_000)]
-		fn found(origin, founder: T::AccountId) {
-			T::FounderOrigin::ensure_origin(origin)?;
+		fn found(origin, founder: T::AccountId, max_members: u32, rules: Vec<u8>) {
+			T::FounderSetOrigin::ensure_origin(origin)?;
 			ensure!(!<Head<T, I>>::exists(), Error::<T, I>::AlreadyFounded);
+			ensure!(max_members > 1, Error::<T, I>::MaxMembers);
 			// This should never fail in the context of this function...
+			<MaxMembers<I>>::put(max_members);
 			Self::add_member(&founder)?;
 			<Head<T, I>>::put(&founder);
+			<Founder<T, I>>::put(&founder);
+			Rules::<T, I>::put(T::Hashing::hash(&rules));
 			Self::deposit_event(RawEvent::Founded(founder));
 		}
+
+		/// Anull the founding of the society.
+		///
+		/// The dispatch origin for this call must be Signed, and the signing account must be both
+		/// the `Founder` and the `Head`. This implies that it may only be done when there is one
+		/// member.
+		///
+		/// # <weight>
+		/// - Two storage reads O(1).
+		/// - Four storage removals O(1).
+		/// - One event.
+		///
+		/// Total Complexity: O(1)
+		/// # </weight>
+		#[weight = SimpleDispatchInfo::FixedNormal(20_000)]
+		fn unfound(origin) {
+			let founder = ensure_signed(origin)?;
+			ensure!(Founder::<T, I>::get() == Some(founder.clone()), Error::<T, I>::NotFounder);
+			ensure!(Head::<T, I>::get() == Some(founder.clone()), Error::<T, I>::NotHead);
+
+			Members::<T, I>::kill();
+			Head::<T, I>::kill();
+			Founder::<T, I>::kill();
+			Rules::<T, I>::kill();
+			Candidates::<T, I>::kill();
+			SuspendedCandidates::<T, I>::remove_all();
+			Self::deposit_event(RawEvent::Unfounded(founder));
+		}
+
 		/// Allow suspension judgement origin to make judgement on a suspended member.
 		///
 		/// If a suspended member is forgiven, we simply add them back as a member, not affecting
@@ -849,7 +892,7 @@ decl_module! {
 		fn judge_suspended_member(origin, who: T::AccountId, forgive: bool) {
 			T::SuspensionJudgementOrigin::ensure_origin(origin)?;
 			ensure!(<SuspendedMembers<T, I>>::exists(&who), Error::<T, I>::NotSuspended);
-			
+
 			if forgive {
 				// Try to add member back to society. Can fail with `MaxMembers` limit.
 				Self::add_member(&who)?;
@@ -1010,34 +1053,40 @@ decl_error! {
 	pub enum Error for Module<T: Trait<I>, I: Instance> {
 		/// An incorrect position was provided.
 		BadPosition,
-		/// User is not a member
+		/// User is not a member.
 		NotMember,
-		/// User is already a member
+		/// User is already a member.
 		AlreadyMember,
-		/// User is suspended
+		/// User is suspended.
 		Suspended,
-		/// User is not suspended
+		/// User is not suspended.
 		NotSuspended,
-		/// Nothing to payout
+		/// Nothing to payout.
 		NoPayout,
-		/// Society already founded
+		/// Society already founded.
 		AlreadyFounded,
-		/// Not enough in pot to accept candidate
+		/// Not enough in pot to accept candidate.
 		InsufficientPot,
-		/// Member is already vouching or banned from vouching again
+		/// Member is already vouching or banned from vouching again.
 		AlreadyVouching,
-		/// Member is not vouching
+		/// Member is not vouching.
 		NotVouching,
-		/// Cannot remove head
+		/// Cannot remove the head of the chain.
 		Head,
-		/// User has already made a bid
+		/// Cannot remove the founder.
+		Founder,
+		/// User has already made a bid.
 		AlreadyBid,
-		/// User is already a candidate
+		/// User is already a candidate.
 		AlreadyCandidate,
-		/// User is not a candidate
+		/// User is not a candidate.
 		NotCandidate,
-		/// Too many members in the society
+		/// Too many members in the society.
 		MaxMembers,
+		/// The caller is not the founder.
+		NotFounder,
+		/// The caller is not the head.
+		NotHead,
 	}
 }
 
@@ -1078,6 +1127,20 @@ decl_event! {
 		DefenderVote(AccountId, bool),
 		/// A new max member count has been set
 		NewMaxMembers(u32),
+		/// Society is unfounded.
+		Unfounded(AccountId),
+	}
+}
+
+/// Simple ensure origin struct to filter for the founder account.
+pub struct EnsureFounder<T>(sp_std::marker::PhantomData<T>);
+impl<T: Trait> EnsureOrigin<T::Origin> for EnsureFounder<T> {
+	type Success = T::AccountId;
+	fn try_origin(o: T::Origin) -> Result<Self::Success, T::Origin> {
+		o.into().and_then(|o| match (o, Founder::<T>::get()) {
+			(system::RawOrigin::Signed(ref who), Some(ref f)) if who == f => Ok(who.clone()),
+			(r, _) => Err(T::Origin::from(r)),
+		})
 	}
 }
 
@@ -1201,17 +1264,18 @@ impl<T: Trait<I>, I: Instance> Module<T, I> {
 	/// removes them from the Members storage item.
 	pub fn remove_member(m: &T::AccountId) -> DispatchResult {
 		ensure!(Self::head() != Some(m.clone()), Error::<T, I>::Head);
+		ensure!(Self::founder() != Some(m.clone()), Error::<T, I>::Founder);
 
-		<Members<T, I>>::mutate(|members|
-			match members.binary_search(&m) {
-				Err(_) => Err(Error::<T, I>::NotMember)?,
-				Ok(i) => {
-					members.remove(i);
-					T::MembershipChanged::change_members_sorted(&[], &[m.clone()], members);
-					Ok(())
-				}
+		let mut members = <Members<T, I>>::get();
+		match members.binary_search(&m) {
+			Err(_) => Err(Error::<T, I>::NotMember)?,
+			Ok(i) => {
+				members.remove(i);
+				T::MembershipChanged::change_members_sorted(&[], &[m.clone()], &members[..]);
+				<Members<T, I>>::put(members);
+				Ok(())
 			}
-		)
+		}
 	}
 
 	/// End the current period and begin a new one.
@@ -1251,7 +1315,7 @@ impl<T: Trait<I>, I: Instance> Module<T, I> {
 					.filter_map(|m| <Votes<T, I>>::take(&candidate, m).map(|v| (v, m)))
 					.inspect(|&(v, _)| if v == Vote::Approve { approval_count += 1 })
 					.collect::<Vec<_>>();
-				
+
 				// Select one of the votes at random.
 				// Note that `Vote::Skeptical` and `Vote::Reject` both reject the candidate.
 				let is_accepted = pick_item(&mut rng, &votes).map(|x| x.0) == Some(Vote::Approve);
@@ -1302,6 +1366,9 @@ impl<T: Trait<I>, I: Instance> Module<T, I> {
 				}
 			}).collect::<Vec<_>>();
 
+			// Clean up all votes.
+			<Votes<T, I>>::remove_all();
+
 			// Reward one of the voters who voted the right way.
 			if !total_slash.is_zero() {
 				if let Some(winner) = pick_item(&mut rng, &rewardees) {
@@ -1325,7 +1392,7 @@ impl<T: Trait<I>, I: Instance> Module<T, I> {
 
 			// if at least one candidate was accepted...
 			if !accepted.is_empty() {
-				// select one as primary, randomly chosen from the accepted, weighted by approvals. 
+				// select one as primary, randomly chosen from the accepted, weighted by approvals.
 				// Choose a random number between 0 and `total_approvals`
 				let primary_point = pick_usize(&mut rng, total_approvals - 1);
 				// Find the zero bid or the user who falls on that point
@@ -1333,7 +1400,7 @@ impl<T: Trait<I>, I: Instance> Module<T, I> {
 					.expect("e.1 of final item == total_approvals; \
 						worst case find will always return that item; qed")
 					.0.clone();
-				
+
 				let accounts = accepted.into_iter().map(|x| x.0).collect::<Vec<_>>();
 
 				// Then write everything back out, signal the changed membership and leave an event.
@@ -1404,7 +1471,7 @@ impl<T: Trait<I>, I: Instance> Module<T, I> {
 	/// Suspend a user, removing them from the member list.
 	fn suspend_member(who: &T::AccountId) {
 		if Self::remove_member(&who).is_ok() {
-			<SuspendedMembers<T, I>>::insert(who, ());
+			<SuspendedMembers<T, I>>::insert(who, true);
 			<Strikes<T, I>>::remove(who);
 			Self::deposit_event(RawEvent::MemberSuspended(who.clone()));
 		}
@@ -1450,7 +1517,7 @@ impl<T: Trait<I>, I: Instance> Module<T, I> {
 				let mut rejection_count = 0;
 				// Tallies total number of approve and reject votes for the defender.
 				members.iter()
-					.filter_map(|m| <DefenderVotes<T, I>>::get(m))
+					.filter_map(|m| <DefenderVotes<T, I>>::take(m))
 					.for_each(|v| {
 						match v {
 							Vote::Approve => approval_count += 1,
@@ -1463,6 +1530,9 @@ impl<T: Trait<I>, I: Instance> Module<T, I> {
 					Self::suspend_member(&defender);
 					*members = Self::members();
 				}
+
+				// Clean up all votes.
+				<DefenderVotes<T, I>>::remove_all();
 			}
 
 			// Start a new defender rotation
@@ -1509,8 +1579,10 @@ impl<T: Trait<I>, I: Instance> Module<T, I> {
 	/// the number of bids would not surpass `MaxMembers` if all were accepted.
 	///
 	/// May be empty.
-	pub fn take_selected(members_len: usize, pot: BalanceOf<T, I>) -> Vec<Bid<T::AccountId, BalanceOf<T, I>>>
-	{
+	pub fn take_selected(
+		members_len: usize,
+		pot: BalanceOf<T, I>
+	) -> Vec<Bid<T::AccountId, BalanceOf<T, I>>> {
 		let max_members = MaxMembers::<I>::get() as usize;
 		// No more than 10 will be returned.
 		let mut max_selections: usize = 10.min(max_members.saturating_sub(members_len));
@@ -1521,7 +1593,7 @@ impl<T: Trait<I>, I: Instance> Module<T, I> {
 
 			// The list of selected candidates
 			let mut selected = Vec::new();
-			
+
 			if bids.len() > 0 {
 				// Can only select at most the length of bids
 				max_selections = max_selections.min(bids.len());
diff --git a/frame/society/src/mock.rs b/frame/society/src/mock.rs
index fc46561fd4fef..b8f249f35ce39 100644
--- a/frame/society/src/mock.rs
+++ b/frame/society/src/mock.rs
@@ -44,7 +44,6 @@ parameter_types! {
 	pub const PeriodSpend: u64 = 1000;
 	pub const MaxLockDuration: u64 = 100;
 	pub const ChallengePeriod: u64 = 8;
-	pub const MaxMembers: u32 = 100;
 
 	pub const BlockHashCount: u64 = 250;
 	pub const MaximumBlockWeight: u32 = 1024;
@@ -104,7 +103,7 @@ impl Trait for Test {
 	type MembershipChanged = ();
 	type RotationPeriod = RotationPeriod;
 	type MaxLockDuration = MaxLockDuration;
-	type FounderOrigin = EnsureSignedBy<FounderSetAccount, u128>;
+	type FounderSetOrigin = EnsureSignedBy<FounderSetAccount, u128>;
 	type SuspensionJudgementOrigin = EnsureSignedBy<SuspensionJudgementSetAccount, u128>;
 	type ChallengePeriod = ChallengePeriod;
 }
@@ -133,6 +132,9 @@ impl EnvBuilder {
 				(40, 50),
 				(50, 50),
 				(60, 50),
+				(70, 50),
+				(80, 50),
+				(90, 50),
 			],
 			pot: 0,
 			max_members: 100,
diff --git a/frame/society/src/tests.rs b/frame/society/src/tests.rs
index 7d3ee06a2abeb..3e5afc47f500a 100644
--- a/frame/society/src/tests.rs
+++ b/frame/society/src/tests.rs
@@ -21,21 +21,61 @@ use mock::*;
 
 use frame_support::{assert_ok, assert_noop};
 use sp_runtime::traits::BadOrigin;
+use sp_core::blake2_256;
 
 #[test]
 fn founding_works() {
-	EnvBuilder::new().with_members(vec![]).execute(|| {
+	EnvBuilder::new().with_max_members(0).with_members(vec![]).execute(|| {
+		// Not set up initially.
+		assert_eq!(Society::founder(), None);
+		assert_eq!(Society::max_members(), 0);
+		assert_eq!(Society::pot(), 0);
 		// Account 1 is set as the founder origin
 		// Account 5 cannot start a society
-		assert_noop!(Society::found(Origin::signed(5), 20), BadOrigin);
+		assert_noop!(Society::found(Origin::signed(5), 20, 100, vec![]), BadOrigin);
 		// Account 1 can start a society, where 10 is the founding member
-		assert_ok!(Society::found(Origin::signed(1), 10));
+		assert_ok!(Society::found(Origin::signed(1), 10, 100, b"be cool".to_vec()));
 		// Society members only include 10
 		assert_eq!(Society::members(), vec![10]);
 		// 10 is the head of the society
 		assert_eq!(Society::head(), Some(10));
+		// ...and also the founder
+		assert_eq!(Society::founder(), Some(10));
+		// 100 members max
+		assert_eq!(Society::max_members(), 100);
+		// rules are correct
+		assert_eq!(Society::rules(), Some(blake2_256(b"be cool").into()));
+		// Pot grows after first rotation period
+		run_to_block(4);
+		assert_eq!(Society::pot(), 1000);
 		// Cannot start another society
-		assert_noop!(Society::found(Origin::signed(1), 20), Error::<Test, _>::AlreadyFounded);
+		assert_noop!(
+			Society::found(Origin::signed(1), 20, 100, vec![]),
+			Error::<Test, _>::AlreadyFounded
+		);
+	});
+}
+
+#[test]
+fn unfounding_works() {
+	EnvBuilder::new().with_max_members(0).with_members(vec![]).execute(|| {
+		// Account 1 sets the founder...
+		assert_ok!(Society::found(Origin::signed(1), 10, 100, vec![]));
+		// Account 2 cannot unfound it as it's not the founder.
+		assert_noop!(Society::unfound(Origin::signed(2)), Error::<Test, _>::NotFounder);
+		// Account 10 can, though.
+		assert_ok!(Society::unfound(Origin::signed(10)));
+
+		// 1 sets the founder to 20 this time
+		assert_ok!(Society::found(Origin::signed(1), 20, 100, vec![]));
+		// Bring in a new member...
+		assert_ok!(Society::bid(Origin::signed(10), 0));
+		run_to_block(4);
+		assert_ok!(Society::vote(Origin::signed(20), 10, true));
+		run_to_block(8);
+
+		// Unfounding won't work now, even though it's from 20.
+		assert_noop!(Society::unfound(Origin::signed(20)), Error::<Test, _>::NotHead);
 	});
 }
 
@@ -248,7 +288,7 @@ fn suspended_member_lifecycle_works() {
 		assert_ok!(Society::add_member(&20));
 		assert_eq!(<Members<Test>>::get(), vec![10, 20]);
 		assert_eq!(Strikes::<Test>::get(20), 0);
-		assert_eq!(<SuspendedMembers<Test>>::get(20), None);
+		assert_eq!(<SuspendedMembers<Test>>::get(20), false);
 
 		// Let's suspend account 20 by giving them 2 strikes by not voting
 		assert_ok!(Society::bid(Origin::signed(30), 0));
@@ -258,29 +298,29 @@ fn suspended_member_lifecycle_works() {
 		run_to_block(16);
 
 		// Strike 2 is accumulated, and 20 is suspended :(
-		assert_eq!(<SuspendedMembers<Test>>::get(20), Some(()));
+		assert_eq!(<SuspendedMembers<Test>>::get(20), true);
 		assert_eq!(<Members<Test>>::get(), vec![10]);
 
 		// Suspended members cannot get payout
 		Society::bump_payout(&20, 10, 100);
 		assert_noop!(Society::payout(Origin::signed(20)), Error::<Test, _>::NotMember);
-		
+
 		// Normal people cannot make judgement
 		assert_noop!(Society::judge_suspended_member(Origin::signed(20), 20, true), BadOrigin);
 
 		// Suspension judgment origin can judge thee
 		// Suspension judgement origin forgives the suspended member
 		assert_ok!(Society::judge_suspended_member(Origin::signed(2), 20, true));
-		assert_eq!(<SuspendedMembers<Test>>::get(20), None);
+		assert_eq!(<SuspendedMembers<Test>>::get(20), false);
 		assert_eq!(<Members<Test>>::get(), vec![10, 20]);
 
 		// Let's suspend them again, directly
 		Society::suspend_member(&20);
-		assert_eq!(<SuspendedMembers<Test>>::get(20), Some(()));
+		assert_eq!(<SuspendedMembers<Test>>::get(20), true);
 		// Suspension judgement origin does not forgive the suspended member
 		assert_ok!(Society::judge_suspended_member(Origin::signed(2), 20, false));
 		// Cleaned up
-		assert_eq!(<SuspendedMembers<Test>>::get(20), None);
+		assert_eq!(<SuspendedMembers<Test>>::get(20), false);
 		assert_eq!(<Members<Test>>::get(), vec![10]);
 		assert_eq!(<Payouts<Test>>::get(20), vec![]);
 	});
@@ -460,10 +500,11 @@ fn unbid_vouch_works() {
 }
 
 #[test]
-fn head_cannot_be_removed() {
+fn founder_and_head_cannot_be_removed() {
 	EnvBuilder::new().execute(|| {
-		// 10 is the only member and head
+		// 10 is the only member, founder, and head
 		assert_eq!(Society::members(), vec![10]);
+		assert_eq!(Society::founder(), Some(10));
 		assert_eq!(Society::head(), Some(10));
 		// 10 can still accumulate strikes
 		assert_ok!(Society::bid(Origin::signed(20), 0));
@@ -485,16 +526,37 @@ fn head_cannot_be_removed() {
 		run_to_block(32);
 		assert_eq!(Society::members(), vec![10, 50]);
 		assert_eq!(Society::head(), Some(50));
+		// Founder is unchanged
+		assert_eq!(Society::founder(), Some(10));
 
-		// 10 can now be suspended for strikes
+		// 50 can still accumulate strikes
 		assert_ok!(Society::bid(Origin::signed(60), 0));
-		run_to_block(36);
-		// The candidate is rejected, so voting approve will give a strike
-		assert_ok!(Society::vote(Origin::signed(10), 60, true));
 		run_to_block(40);
-		assert_eq!(Strikes::<Test>::get(10), 0);
-		assert_eq!(<SuspendedMembers<Test>>::get(10), Some(()));
-		assert_eq!(Society::members(), vec![50]);
+		assert_eq!(Strikes::<Test>::get(50), 1);
+		assert_ok!(Society::bid(Origin::signed(70), 0));
+		run_to_block(48);
+		assert_eq!(Strikes::<Test>::get(50), 2);
+
+		// Replace the head
+		assert_ok!(Society::bid(Origin::signed(80), 0));
+		run_to_block(52);
+		assert_ok!(Society::vote(Origin::signed(10), 80, true));
+		assert_ok!(Society::vote(Origin::signed(50), 80, true));
+		assert_ok!(Society::defender_vote(Origin::signed(10), true)); // Keep defender around
+		run_to_block(56);
+		assert_eq!(Society::members(), vec![10, 50, 80]);
+		assert_eq!(Society::head(), Some(80));
+		assert_eq!(Society::founder(), Some(10));
+
+		// 50 can now be suspended for strikes
+		assert_ok!(Society::bid(Origin::signed(90), 0));
+		run_to_block(60);
+		// The candidate is rejected, so voting approve will give a strike
+		assert_ok!(Society::vote(Origin::signed(50), 90, true));
+		run_to_block(64);
+		assert_eq!(Strikes::<Test>::get(50), 0);
+		assert_eq!(<SuspendedMembers<Test>>::get(50), true);
+		assert_eq!(Society::members(), vec![10, 80]);
 	});
 }
 
@@ -505,6 +567,11 @@ fn challenges_work() {
 		assert_ok!(Society::add_member(&20));
 		assert_ok!(Society::add_member(&30));
 		assert_ok!(Society::add_member(&40));
+		// Votes are empty
+		assert_eq!(<DefenderVotes<Test>>::get(10), None);
+		assert_eq!(<DefenderVotes<Test>>::get(20), None);
+		assert_eq!(<DefenderVotes<Test>>::get(30), None);
+		assert_eq!(<DefenderVotes<Test>>::get(40), None);
 		// Check starting point
 		assert_eq!(Society::members(), vec![10, 20, 30, 40]);
 		assert_eq!(Society::defender(), None);
@@ -528,6 +595,11 @@ fn challenges_work() {
 		run_to_block(24);
 		// 20 survives
 		assert_eq!(Society::members(), vec![10, 20, 30, 40]);
+		// Votes are reset
+		assert_eq!(<DefenderVotes<Test>>::get(10), None);
+		assert_eq!(<DefenderVotes<Test>>::get(20), None);
+		assert_eq!(<DefenderVotes<Test>>::get(30), None);
+		assert_eq!(<DefenderVotes<Test>>::get(40), None);
 		// One more time
 		assert_eq!(Society::defender(), Some(20));
 		// 2 people say accept, 2 reject
@@ -538,9 +610,14 @@ fn challenges_work() {
 		run_to_block(32);
 		// 20 is suspended
 		assert_eq!(Society::members(), vec![10, 30, 40]);
-		assert_eq!(Society::suspended_member(20), Some(()));
+		assert_eq!(Society::suspended_member(20), true);
 		// New defender is chosen
 		assert_eq!(Society::defender(), Some(40));
+		// Votes are reset
+		assert_eq!(<DefenderVotes<Test>>::get(10), None);
+		assert_eq!(<DefenderVotes<Test>>::get(20), None);
+		assert_eq!(<DefenderVotes<Test>>::get(30), None);
+		assert_eq!(<DefenderVotes<Test>>::get(40), None);
 	});
 }
 
@@ -610,7 +687,7 @@ fn vouching_handles_removed_member_with_bid() {
 		assert_eq!(<Vouching<Test>>::get(20), Some(VouchingStatus::Vouching));
 		// Suspend that member
 		Society::suspend_member(&20);
-		assert_eq!(<SuspendedMembers<Test>>::get(20), Some(()));
+		assert_eq!(<SuspendedMembers<Test>>::get(20), true);
 		// Nothing changes yet
 		assert_eq!(<Bids<Test>>::get(), vec![create_bid(1000, 30, BidKind::Vouch(20, 100))]);
 		assert_eq!(<Vouching<Test>>::get(20), Some(VouchingStatus::Vouching));
@@ -637,7 +714,7 @@ fn vouching_handles_removed_member_with_candidate() {
 		assert_eq!(Society::candidates(), vec![create_bid(1000, 30, BidKind::Vouch(20, 100))]);
 		// Suspend that member
 		Society::suspend_member(&20);
-		assert_eq!(<SuspendedMembers<Test>>::get(20), Some(()));
+		assert_eq!(<SuspendedMembers<Test>>::get(20), true);
 		// Nothing changes yet
 		assert_eq!(Society::candidates(), vec![create_bid(1000, 30, BidKind::Vouch(20, 100))]);
 		assert_eq!(<Vouching<Test>>::get(20), Some(VouchingStatus::Vouching));
diff --git a/frame/staking/Cargo.toml b/frame/staking/Cargo.toml
index e3e6fcbe7badf..52584cf47f47d 100644
--- a/frame/staking/Cargo.toml
+++ b/frame/staking/Cargo.toml
@@ -6,7 +6,6 @@ edition = "2018"
 
 [dependencies]
 serde = { version = "1.0.101", optional = true }
-safe-mix = { version = "1.0.0", default-features = false }
 codec = { package = "parity-scale-codec", version = "1.0.0", default-features = false, features = ["derive"] }
 sp-keyring = { version = "2.0.0", optional = true, path = "../../primitives/keyring" }
 sp-std = { version = "2.0.0", default-features = false, path = "../../primitives/std" }
@@ -31,7 +30,6 @@ migrate = []
 default = ["std"]
 std = [
 	"serde",
-	"safe-mix/std",
 	"sp-keyring",
 	"codec/std",
 	"sp-std/std",
diff --git a/frame/staking/src/lib.rs b/frame/staking/src/lib.rs
index a59aa5d0c8e83..326a01599034c 100644
--- a/frame/staking/src/lib.rs
+++ b/frame/staking/src/lib.rs
@@ -283,7 +283,7 @@ use sp_staking::{
 use sp_runtime::{Serialize, Deserialize};
 use frame_system::{self as system, ensure_signed, ensure_root};
 
-use sp_phragmen::{ExtendedBalance, PhragmenStakedAssignment};
+use sp_phragmen::ExtendedBalance;
 
 const DEFAULT_MINIMUM_VALIDATOR_COUNT: u32 = 4;
 const MAX_NOMINATIONS: usize = 16;
@@ -1508,12 +1508,10 @@ impl<T: Trait> Module<T> {
 				.collect::<Vec<T::AccountId>>();
 			let assignments = phragmen_result.assignments;
 
-			let to_votes = |b: BalanceOf<T>|
-				<T::CurrencyToVote as Convert<BalanceOf<T>, u64>>::convert(b) as ExtendedBalance;
 			let to_balance = |e: ExtendedBalance|
 				<T::CurrencyToVote as Convert<ExtendedBalance, BalanceOf<T>>>::convert(e);
 
-			let mut supports = sp_phragmen::build_support_map::<_, _, _, T::CurrencyToVote>(
+			let supports = sp_phragmen::build_support_map::<_, _, _, T::CurrencyToVote>(
 				&elected_stashes,
 				&assignments,
 				Self::slashable_balance_of,
@@ -1628,7 +1626,6 @@ impl<T: Trait> Module<T> {
 	/// For each element in the iterator the given number of points in u32 is added to the
 	/// validator, thus duplicates are handled.
 	pub fn reward_by_indices(validators_points: impl IntoIterator<Item = (u32, u32)>) {
-		// TODO: This can be optimised once #3302 is implemented.
 		let current_elected_len = <Module<T>>::current_elected().len() as u32;
 
 		CurrentEraPointsEarned::mutate(|rewards| {
diff --git a/frame/staking/src/slashing.rs b/frame/staking/src/slashing.rs
index 6d591603fdbcc..7322b9a1d3118 100644
--- a/frame/staking/src/slashing.rs
+++ b/frame/staking/src/slashing.rs
@@ -649,9 +649,6 @@ fn pay_reporters<T: Trait>(
 	T::Slash::on_unbalanced(value_slashed);
 }
 
-// TODO: function for undoing a slash.
-//
-
 #[cfg(test)]
 mod tests {
 	use super::*;
diff --git a/frame/staking/src/tests.rs b/frame/staking/src/tests.rs
index 555edac979d87..c290c6a8581d4 100644
--- a/frame/staking/src/tests.rs
+++ b/frame/staking/src/tests.rs
@@ -90,29 +90,16 @@ fn basic_setup_works() {
 		);
 		assert_eq!(Staking::nominators(101).unwrap().targets, vec![11, 21]);
 
-		if cfg!(feature = "equalize") {
-			assert_eq!(
-				Staking::stakers(11),
-				Exposure { total: 1250, own: 1000, others: vec![ IndividualExposure { who: 101, value: 250 }] }
-			);
-			assert_eq!(
-				Staking::stakers(21),
-				Exposure { total: 1250, own: 1000, others: vec![ IndividualExposure { who: 101, value: 250 }] }
-			);
-			// initial slot_stake
-			assert_eq!(Staking::slot_stake(),  1250);
-		} else {
-			assert_eq!(
-				Staking::stakers(11),
-				Exposure { total: 1125, own: 1000, others: vec![ IndividualExposure { who: 101, value: 125 }] }
-			);
-			assert_eq!(
-				Staking::stakers(21),
-				Exposure { total: 1375, own: 1000, others: vec![ IndividualExposure { who: 101, value: 375 }] }
-			);
-			// initial slot_stake
-			assert_eq!(Staking::slot_stake(),  1125);
-		}
+		assert_eq!(
+			Staking::stakers(11),
+			Exposure { total: 1125, own: 1000, others: vec![ IndividualExposure { who: 101, value: 125 }] }
+		);
+		assert_eq!(
+			Staking::stakers(21),
+			Exposure { total: 1375, own: 1000, others: vec![ IndividualExposure { who: 101, value: 375 }] }
+		);
+		// initial slot_stake
+		assert_eq!(Staking::slot_stake(),  1125);
 
 
 		// The number of validators required.
@@ -488,57 +475,30 @@ fn nominating_and_rewards_should_work() {
 
 			// ------ check the staked value of all parties.
 
-			if cfg!(feature = "equalize") {
-				// total expo of 10, with 1200 coming from nominators (externals), according to phragmen.
-				assert_eq!(Staking::stakers(11).own, 1000);
-				assert_eq_error_rate!(Staking::stakers(11).total, 1000 + 1000, 2);
-				// 2 and 4 supported 10, each with stake 600, according to phragmen.
-				assert_eq!(
-					Staking::stakers(11).others.iter().map(|e| e.value).collect::<Vec<BalanceOf<Test>>>(),
-					vec![600, 400]
-				);
-				assert_eq!(
-					Staking::stakers(11).others.iter().map(|e| e.who).collect::<Vec<u64>>(),
-					vec![3, 1]
-				);
-				// total expo of 20, with 500 coming from nominators (externals), according to phragmen.
-				assert_eq!(Staking::stakers(21).own, 1000);
-				assert_eq_error_rate!(Staking::stakers(21).total, 1000 + 1000, 2);
-				// 2 and 4 supported 20, each with stake 250, according to phragmen.
-				assert_eq!(
-					Staking::stakers(21).others.iter().map(|e| e.value).collect::<Vec<BalanceOf<Test>>>(),
-					vec![400, 600]
-				);
-				assert_eq!(
-					Staking::stakers(21).others.iter().map(|e| e.who).collect::<Vec<u64>>(),
-					vec![3, 1]
-				);
-			} else {
-				// total expo of 10, with 1200 coming from nominators (externals), according to phragmen.
-				assert_eq!(Staking::stakers(11).own, 1000);
-				assert_eq!(Staking::stakers(11).total, 1000 + 800);
-				// 2 and 4 supported 10, each with stake 600, according to phragmen.
-				assert_eq!(
-					Staking::stakers(11).others.iter().map(|e| e.value).collect::<Vec<BalanceOf<Test>>>(),
-					vec![400, 400]
-				);
-				assert_eq!(
-					Staking::stakers(11).others.iter().map(|e| e.who).collect::<Vec<u64>>(),
-					vec![3, 1]
-				);
-				// total expo of 20, with 500 coming from nominators (externals), according to phragmen.
-				assert_eq!(Staking::stakers(21).own, 1000);
-				assert_eq_error_rate!(Staking::stakers(21).total, 1000 + 1200, 2);
-				// 2 and 4 supported 20, each with stake 250, according to phragmen.
-				assert_eq!(
-					Staking::stakers(21).others.iter().map(|e| e.value).collect::<Vec<BalanceOf<Test>>>(),
-					vec![600, 600]
-				);
-				assert_eq!(
-					Staking::stakers(21).others.iter().map(|e| e.who).collect::<Vec<u64>>(),
-					vec![3, 1]
-				);
-			}
+			// total expo of 10, with 1200 coming from nominators (externals), according to phragmen.
+			assert_eq!(Staking::stakers(11).own, 1000);
+			assert_eq!(Staking::stakers(11).total, 1000 + 800);
+			// 2 and 4 supported 10, each with stake 600, according to phragmen.
+			assert_eq!(
+				Staking::stakers(11).others.iter().map(|e| e.value).collect::<Vec<BalanceOf<Test>>>(),
+				vec![400, 400]
+			);
+			assert_eq!(
+				Staking::stakers(11).others.iter().map(|e| e.who).collect::<Vec<u64>>(),
+				vec![3, 1]
+			);
+			// total expo of 20, with 500 coming from nominators (externals), according to phragmen.
+			assert_eq!(Staking::stakers(21).own, 1000);
+			assert_eq_error_rate!(Staking::stakers(21).total, 1000 + 1200, 2);
+			// 2 and 4 supported 20, each with stake 250, according to phragmen.
+			assert_eq!(
+				Staking::stakers(21).others.iter().map(|e| e.value).collect::<Vec<BalanceOf<Test>>>(),
+				vec![600, 600]
+			);
+			assert_eq!(
+				Staking::stakers(21).others.iter().map(|e| e.who).collect::<Vec<u64>>(),
+				vec![3, 1]
+			);
 
 			// They are not chosen anymore
 			assert_eq!(Staking::stakers(31).total, 0);
@@ -559,59 +519,31 @@ fn nominating_and_rewards_should_work() {
 
 			let payout_for_10 = total_payout_1 / 3;
 			let payout_for_20 = 2 * total_payout_1 / 3;
-			if cfg!(feature = "equalize") {
-				// Nominator 2: has [400 / 2000 ~ 1 / 5 from 10] + [600 / 2000 ~ 3 / 10 from 20]'s reward.
-				assert_eq_error_rate!(
-					Balances::total_balance(&2),
-					initial_balance + payout_for_10 / 5 + payout_for_20 * 3 / 10,
-					2,
-				);
-				// Nominator 4: has [400 / 2000 ~ 1 / 5 from 20] + [600 / 2000 ~ 3 / 10 from 10]'s reward.
-				assert_eq_error_rate!(
-					Balances::total_balance(&4),
-					initial_balance + payout_for_20 / 5 + payout_for_10 * 3 / 10,
-					2,
-				);
-
-				// Validator 10: got 1000 / 2000 external stake.
-				assert_eq_error_rate!(
-					Balances::total_balance(&10),
-					initial_balance + payout_for_10 / 2,
-					1,
-				);
-				// Validator 20: got 1000 / 2000 external stake.
-				assert_eq_error_rate!(
-					Balances::total_balance(&20),
-					initial_balance + payout_for_20 / 2,
-					1,
-				);
-			} else {
-				// Nominator 2: has [400/1800 ~ 2/9 from 10] + [600/2200 ~ 3/11 from 20]'s reward. ==> 2/9 + 3/11
-				assert_eq_error_rate!(
-					Balances::total_balance(&2),
-					initial_balance + (2 * payout_for_10 / 9 + 3 * payout_for_20 / 11),
-					1,
-				);
-				// Nominator 4: has [400/1800 ~ 2/9 from 10] + [600/2200 ~ 3/11 from 20]'s reward. ==> 2/9 + 3/11
-				assert_eq_error_rate!(
-					Balances::total_balance(&4),
-					initial_balance + (2 * payout_for_10 / 9 + 3 * payout_for_20 / 11),
-					1,
-				);
-
-				// Validator 10: got 800 / 1800 external stake => 8/18 =? 4/9 => Validator's share = 5/9
-				assert_eq_error_rate!(
-					Balances::total_balance(&10),
-					initial_balance + 5 * payout_for_10 / 9,
-					1,
-				);
-				// Validator 20: got 1200 / 2200 external stake => 12/22 =? 6/11 => Validator's share = 5/11
-				assert_eq_error_rate!(
-					Balances::total_balance(&20),
-					initial_balance + 5 * payout_for_20 / 11,
-					1,
-				);
-			}
+			// Nominator 2: has [400/1800 ~ 2/9 from 10] + [600/2200 ~ 3/11 from 20]'s reward. ==> 2/9 + 3/11
+			assert_eq_error_rate!(
+				Balances::total_balance(&2),
+				initial_balance + (2 * payout_for_10 / 9 + 3 * payout_for_20 / 11),
+				1,
+			);
+			// Nominator 4: has [400/1800 ~ 2/9 from 10] + [600/2200 ~ 3/11 from 20]'s reward. ==> 2/9 + 3/11
+			assert_eq_error_rate!(
+				Balances::total_balance(&4),
+				initial_balance + (2 * payout_for_10 / 9 + 3 * payout_for_20 / 11),
+				1,
+			);
+
+			// Validator 10: got 800 / 1800 external stake => 8/18 =? 4/9 => Validator's share = 5/9
+			assert_eq_error_rate!(
+				Balances::total_balance(&10),
+				initial_balance + 5 * payout_for_10 / 9,
+				1,
+			);
+			// Validator 20: got 1200 / 2200 external stake => 12/22 =? 6/11 => Validator's share = 5/11
+			assert_eq_error_rate!(
+				Balances::total_balance(&20),
+				initial_balance + 5 * payout_for_20 / 11,
+				1,
+			);
 
 			check_exposure_all();
 			check_nominator_all();
@@ -1778,51 +1710,6 @@ fn bond_with_little_staked_value_bounded_by_slot_stake() {
 		});
 }
 
-#[cfg(feature = "equalize")]
-#[test]
-fn phragmen_linear_worse_case_equalize() {
-	ExtBuilder::default()
-		.nominate(false)
-		.validator_pool(true)
-		.fair(true)
-		.build()
-		.execute_with(|| {
-			bond_validator(50, 1000);
-			bond_validator(60, 1000);
-			bond_validator(70, 1000);
-
-			bond_nominator(2, 2000, vec![11]);
-			bond_nominator(4, 1000, vec![11, 21]);
-			bond_nominator(6, 1000, vec![21, 31]);
-			bond_nominator(8, 1000, vec![31, 41]);
-			bond_nominator(110, 1000, vec![41, 51]);
-			bond_nominator(120, 1000, vec![51, 61]);
-			bond_nominator(130, 1000, vec![61, 71]);
-
-			for i in &[10, 20, 30, 40, 50, 60, 70] {
-				assert_ok!(Staking::set_payee(Origin::signed(*i), RewardDestination::Controller));
-			}
-
-			assert_eq_uvec!(validator_controllers(), vec![40, 30]);
-			assert_ok!(Staking::set_validator_count(Origin::ROOT, 7));
-
-			start_era(1);
-
-			assert_eq_uvec!(validator_controllers(), vec![10, 60, 40, 20, 50, 30, 70]);
-
-			assert_eq_error_rate!(Staking::stakers(11).total, 3000, 2);
-			assert_eq_error_rate!(Staking::stakers(21).total, 2255, 2);
-			assert_eq_error_rate!(Staking::stakers(31).total, 2255, 2);
-			assert_eq_error_rate!(Staking::stakers(41).total, 1925, 2);
-			assert_eq_error_rate!(Staking::stakers(51).total, 1870, 2);
-			assert_eq_error_rate!(Staking::stakers(61).total, 1890, 2);
-			assert_eq_error_rate!(Staking::stakers(71).total, 1800, 2);
-
-			check_exposure_all();
-			check_nominator_all();
-		})
-}
-
 #[test]
 fn new_era_elects_correct_number_of_validators() {
 	ExtBuilder::default()
@@ -2195,9 +2082,6 @@ fn reporters_receive_their_slice() {
 	// amount.
 	ExtBuilder::default().build().execute_with(|| {
 		// The reporters' reward is calculated from the total exposure.
-		#[cfg(feature = "equalize")]
-		let initial_balance = 1250;
-		#[cfg(not(feature = "equalize"))]
 		let initial_balance = 1125;
 
 		assert_eq!(Staking::stakers(&11).total, initial_balance);
@@ -2229,9 +2113,6 @@ fn subsequent_reports_in_same_span_pay_out_less() {
 	// amount.
 	ExtBuilder::default().build().execute_with(|| {
 		// The reporters' reward is calculated from the total exposure.
-		#[cfg(feature = "equalize")]
-		let initial_balance = 1250;
-		#[cfg(not(feature = "equalize"))]
 		let initial_balance = 1125;
 
 		assert_eq!(Staking::stakers(&11).total, initial_balance);
diff --git a/frame/support/Cargo.toml b/frame/support/Cargo.toml
index 1695375d36832..d8460ef7e8aea 100644
--- a/frame/support/Cargo.toml
+++ b/frame/support/Cargo.toml
@@ -8,7 +8,7 @@ edition = "2018"
 log = "0.4"
 serde = { version = "1.0.101", optional = true, features = ["derive"] }
 codec = { package = "parity-scale-codec", version = "1.0.6", default-features = false, features = ["derive"] }
-frame-metadata = { version = "2.0.0", default-features = false, path = "../metadata" }
+frame-metadata = { version = "10.0.0", default-features = false, path = "../metadata" }
 sp-std = { version = "2.0.0", default-features = false, path = "../../primitives/std" }
 sp-io ={ path = "../../primitives/io", default-features = false }
 sp-runtime = { version = "2.0.0", default-features = false, path = "../../primitives/runtime" }
@@ -18,7 +18,7 @@ sp-inherents = { version = "2.0.0", default-features = false, path = "../../prim
 frame-support-procedural = { version = "2.0.0", path = "./procedural" }
 paste = "0.1.6"
 once_cell = { version = "0.2.4", default-features = false, optional = true }
-sp-state-machine = { version = "2.0.0", optional = true, path = "../../primitives/state-machine" }
+sp-state-machine = { version = "0.8", optional = true, path = "../../primitives/state-machine" }
 bitmask = { version = "0.5.0", default-features = false }
 impl-trait-for-tuples = "0.1.3"
 tracing = { version = "0.1.10", optional = true }
diff --git a/frame/support/src/storage/generator/mod.rs b/frame/support/src/storage/generator/mod.rs
index 386e3d1cecaef..476c6d4472054 100644
--- a/frame/support/src/storage/generator/mod.rs
+++ b/frame/support/src/storage/generator/mod.rs
@@ -20,6 +20,8 @@
 //! implementation of StorageValue for this type).
 //!
 //! They are used by `decl_storage`.
+//!
+//! This is internal api and is subject to change.
 
 mod linked_map;
 mod map;
diff --git a/frame/support/src/storage/mod.rs b/frame/support/src/storage/mod.rs
index 0908adae3b604..f629ac3eb91a1 100644
--- a/frame/support/src/storage/mod.rs
+++ b/frame/support/src/storage/mod.rs
@@ -23,6 +23,7 @@ use crate::{traits::Len, hash::{Twox128, StorageHasher}};
 pub mod unhashed;
 pub mod hashed;
 pub mod child;
+#[doc(hidden)]
 pub mod generator;
 
 /// A trait for working with macro-generated storage values under the substrate storage API.
diff --git a/frame/support/src/weights.rs b/frame/support/src/weights.rs
index f1092b500230b..e44ab16458836 100644
--- a/frame/support/src/weights.rs
+++ b/frame/support/src/weights.rs
@@ -236,6 +236,36 @@ impl SimpleDispatchInfo {
 	}
 }
 
+/// A struct to represent a weight which is a function of the input arguments. The given items have
+/// the following types:
+///
+/// - `F`: a closure with the same argument list as the dispatched, wrapped in a tuple.
+/// - `DispatchClass`: class of the dispatch.
+/// - `bool`: whether this dispatch pays fee or not.
+pub struct FunctionOf<F>(pub F, pub DispatchClass, pub bool);
+
+impl<Args, F> WeighData<Args> for FunctionOf<F>
+where
+	F : Fn(Args) -> Weight
+{
+	fn weigh_data(&self, args: Args) -> Weight {
+		(self.0)(args)
+	}
+}
+
+impl<Args, F> ClassifyDispatch<Args> for FunctionOf<F> {
+	fn classify_dispatch(&self, _: Args) -> DispatchClass {
+		self.1.clone()
+	}
+}
+
+impl<T, F> PaysFee<T> for FunctionOf<F> {
+	fn pays_fee(&self, _: T) -> bool {
+		self.2
+	}
+}
+
+
 /// Implementation for unchecked extrinsic.
 impl<Address, Call, Signature, Extra> GetDispatchInfo
 	for UncheckedExtrinsic<Address, Call, Signature, Extra>
@@ -271,3 +301,46 @@ impl<Call: Encode, Extra: Encode> GetDispatchInfo for sp_runtime::testing::TestX
 		}
 	}
 }
+
+#[cfg(test)]
+#[allow(dead_code)]
+mod tests {
+	use crate::decl_module;
+	use super::*;
+
+	pub trait Trait {
+		type Origin;
+		type Balance;
+		type BlockNumber;
+	}
+
+	pub struct TraitImpl {}
+
+	impl Trait for TraitImpl {
+		type Origin = u32;
+		type BlockNumber = u32;
+		type Balance = u32;
+	}
+
+	decl_module! {
+		pub struct Module<T: Trait> for enum Call where origin: T::Origin {
+			// no arguments, fixed weight
+			#[weight = SimpleDispatchInfo::FixedNormal(1000)]
+			fn f0(_origin) { unimplemented!(); }
+
+			// weight = a x 10 + b
+			#[weight = FunctionOf(|args: (&u32, &u32)| args.0 * 10 + args.1, DispatchClass::Normal, true)]
+			fn f11(_origin, _a: u32, _eb: u32) { unimplemented!(); }
+
+			#[weight = FunctionOf(|_: (&u32, &u32)| 0, DispatchClass::Operational, true)]
+			fn f12(_origin, _a: u32, _eb: u32) { unimplemented!(); }
+		}
+	}
+
+	#[test]
+	fn weights_are_correct() {
+		assert_eq!(Call::<TraitImpl>::f11(10, 20).get_dispatch_info().weight, 120);
+		assert_eq!(Call::<TraitImpl>::f11(10, 20).get_dispatch_info().class, DispatchClass::Normal);
+		assert_eq!(Call::<TraitImpl>::f0().get_dispatch_info().weight, 1000);
+	}
+}
diff --git a/frame/support/test/Cargo.toml b/frame/support/test/Cargo.toml
index 92dc32e478f1d..0c73dcd65e4b8 100644
--- a/frame/support/test/Cargo.toml
+++ b/frame/support/test/Cargo.toml
@@ -8,7 +8,7 @@ edition = "2018"
 serde = { version = "1.0.101", default-features = false, features = ["derive"] }
 codec = { package = "parity-scale-codec", version = "1.0.0", default-features = false, features = ["derive"] }
 sp-io ={ path = "../../../primitives/io", default-features = false }
-sp-state-machine = { version = "2.0.0", optional = true, path = "../../../primitives/state-machine" }
+sp-state-machine = { version = "0.8", optional = true, path = "../../../primitives/state-machine" }
 frame-support = { version = "2.0.0", default-features = false, path = "../" }
 sp-inherents = { version = "2.0.0", default-features = false, path = "../../../primitives/inherents" }
 sp-runtime = { version = "2.0.0", default-features = false, path = "../../../primitives/runtime" }
diff --git a/frame/system/Cargo.toml b/frame/system/Cargo.toml
index 227aecee2ee43..098c320f454e5 100644
--- a/frame/system/Cargo.toml
+++ b/frame/system/Cargo.toml
@@ -6,7 +6,6 @@ edition = "2018"
 
 [dependencies]
 serde = { version = "1.0.101", optional = true, features = ["derive"] }
-safe-mix = { version = "1.0.0", default-features = false }
 codec = { package = "parity-scale-codec", version = "1.0.0", default-features = false, features = ["derive"] }
 sp-core = { version = "2.0.0", default-features = false, path = "../../primitives/core" }
 sp-std = { version = "2.0.0", default-features = false, path = "../../primitives/std" }
@@ -18,12 +17,13 @@ impl-trait-for-tuples = "0.1.3"
 
 [dev-dependencies]
 criterion = "0.2.11"
+sp-externalities = { version = "0.8.0", path = "../../primitives/externalities" }
+substrate-test-runtime-client = { version = "2.0.0", path = "../../test-utils/runtime/client" }
 
 [features]
 default = ["std"]
 std = [
 	"serde",
-	"safe-mix/std",
 	"codec/std",
 	"sp-core/std",
 	"sp-std/std",
diff --git a/frame/system/src/lib.rs b/frame/system/src/lib.rs
index 9e7678a7ede34..478fd780b98fa 100644
--- a/frame/system/src/lib.rs
+++ b/frame/system/src/lib.rs
@@ -110,7 +110,7 @@ use sp_runtime::{
 	},
 };
 
-use sp_core::storage::well_known_keys;
+use sp_core::{ChangesTrieConfiguration, storage::well_known_keys};
 use frame_support::{
 	decl_module, decl_event, decl_storage, decl_error, storage, Parameter,
 	traits::{Contains, Get, ModuleToIndex, OnReapAccount},
@@ -121,9 +121,6 @@ use codec::{Encode, Decode};
 #[cfg(any(feature = "std", test))]
 use sp_io::TestExternalities;
 
-#[cfg(any(feature = "std", test))]
-use sp_core::ChangesTrieConfiguration;
-
 pub mod offchain;
 
 /// Handler for when a new account has been created.
@@ -259,11 +256,56 @@ decl_module! {
 			storage::unhashed::put_raw(well_known_keys::HEAP_PAGES, &pages.encode());
 		}
 
-		/// Set the new code.
+		/// Set the new runtime code.
+		#[weight = SimpleDispatchInfo::FixedOperational(200_000)]
+		pub fn set_code(origin, code: Vec<u8>) {
+			ensure_root(origin)?;
+
+			let current_version = T::Version::get();
+			let new_version = sp_io::misc::runtime_version(&code)
+				.and_then(|v| RuntimeVersion::decode(&mut &v[..]).ok())
+				.ok_or_else(|| Error::<T>::FailedToExtractRuntimeVersion)?;
+
+			if new_version.spec_name != current_version.spec_name {
+				Err(Error::<T>::InvalidSpecName)?
+			}
+
+			if new_version.spec_version < current_version.spec_version {
+				Err(Error::<T>::SpecVersionNotAllowedToDecrease)?
+			} else if new_version.spec_version == current_version.spec_version {
+				if new_version.impl_version < current_version.impl_version {
+					Err(Error::<T>::ImplVersionNotAllowedToDecrease)?
+				} else if new_version.impl_version == current_version.impl_version {
+					Err(Error::<T>::SpecOrImplVersionNeedToIncrease)?
+				}
+			}
+
+			storage::unhashed::put_raw(well_known_keys::CODE, &code);
+		}
+
+		/// Set the new runtime code without doing any checks of the given `code`.
 		#[weight = SimpleDispatchInfo::FixedOperational(200_000)]
-		pub fn set_code(origin, new: Vec<u8>) {
+		pub fn set_code_without_checks(origin, code: Vec<u8>) {
+			ensure_root(origin)?;
+			storage::unhashed::put_raw(well_known_keys::CODE, &code);
+		}
+
+		/// Set the new changes trie configuration.
+		#[weight = SimpleDispatchInfo::FixedOperational(20_000)]
+		pub fn set_changes_trie_config(origin, changes_trie_config: Option<ChangesTrieConfiguration>) {
 			ensure_root(origin)?;
-			storage::unhashed::put_raw(well_known_keys::CODE, &new);
+			match changes_trie_config.clone() {
+				Some(changes_trie_config) => storage::unhashed::put_raw(
+					well_known_keys::CHANGES_TRIE_CONFIG,
+					&changes_trie_config.encode(),
+				),
+				None => storage::unhashed::kill(well_known_keys::CHANGES_TRIE_CONFIG),
+			}
+
+			let log = generic::DigestItem::ChangesTrieSignal(
+				generic::ChangesTrieSignal::NewConfiguration(changes_trie_config),
+			);
+			Self::deposit_log(log.into());
 		}
 
 		/// Set some items of storage.
@@ -327,7 +369,24 @@ decl_event!(
 
 decl_error! {
 	/// Error for the System module
-	pub enum Error for Module<T: Trait> {}
+	pub enum Error for Module<T: Trait> {
+		/// The name of specification does not match between the current runtime
+		/// and the new runtime.
+		InvalidSpecName,
+		/// The specification version is not allowed to decrease between the current runtime
+		/// and the new runtime.
+		SpecVersionNotAllowedToDecrease,
+		/// The implementation version is not allowed to decrease between the current runtime
+		/// and the new runtime.
+		ImplVersionNotAllowedToDecrease,
+		/// The specification or the implementation version need to increase between the
+		/// current runtime and the new runtime.
+		SpecOrImplVersionNeedToIncrease,
+		/// Failed to extract the runtime version from the new runtime.
+		///
+		/// Either calling `Core_version` or decoding `RuntimeVersion` failed.
+		FailedToExtractRuntimeVersion,
+	}
 }
 
 /// Origin for the System module.
@@ -1189,6 +1248,14 @@ mod tests {
 		pub const MaximumBlockWeight: Weight = 1024;
 		pub const AvailableBlockRatio: Perbill = Perbill::from_percent(75);
 		pub const MaximumBlockLength: u32 = 1024;
+		pub const Version: RuntimeVersion = RuntimeVersion {
+			spec_name: sp_version::create_runtime_str!("test"),
+			impl_name: sp_version::create_runtime_str!("system-test"),
+			authoring_version: 1,
+			spec_version: 1,
+			impl_version: 1,
+			apis: sp_version::create_apis_vec!([]),
+		};
 	}
 
 	impl Trait for Test {
@@ -1206,7 +1273,7 @@ mod tests {
 		type MaximumBlockWeight = MaximumBlockWeight;
 		type AvailableBlockRatio = AvailableBlockRatio;
 		type MaximumBlockLength = MaximumBlockLength;
-		type Version = ();
+		type Version = Version;
 		type ModuleToIndex = ();
 	}
 
@@ -1503,7 +1570,7 @@ mod tests {
 				.validate(&1, CALL, op, len)
 				.unwrap()
 				.priority;
-			assert_eq!(priority, Bounded::max_value());
+			assert_eq!(priority, u64::max_value());
 		})
 	}
 
@@ -1562,4 +1629,65 @@ mod tests {
 			assert_eq!(ext.validate(&1, CALL, normal, len).unwrap().longevity, 15);
 		})
 	}
+
+
+	#[test]
+	fn set_code_checks_works() {
+		struct CallInWasm(Vec<u8>);
+
+		impl sp_core::traits::CallInWasm for CallInWasm {
+			fn call_in_wasm(
+				&self,
+				_: &[u8],
+				_: &str,
+				_: &[u8],
+				_: &mut dyn sp_externalities::Externalities,
+			) -> Result<Vec<u8>, String> {
+				Ok(self.0.clone())
+			}
+		}
+
+		let test_data = vec![
+			("test", 1, 2, Ok(())),
+			("test", 1, 1, Err(Error::<Test>::SpecOrImplVersionNeedToIncrease)),
+			("test2", 1, 1, Err(Error::<Test>::InvalidSpecName)),
+			("test", 2, 1, Ok(())),
+			("test", 0, 1, Err(Error::<Test>::SpecVersionNotAllowedToDecrease)),
+			("test", 1, 0, Err(Error::<Test>::ImplVersionNotAllowedToDecrease)),
+		];
+
+		for (spec_name, spec_version, impl_version, expected) in test_data.into_iter() {
+			let version = RuntimeVersion {
+				spec_name: spec_name.into(),
+				spec_version,
+				impl_version,
+				..Default::default()
+			};
+			let call_in_wasm = CallInWasm(version.encode());
+
+			let mut ext = new_test_ext();
+			ext.register_extension(sp_core::traits::CallInWasmExt::new(call_in_wasm));
+			ext.execute_with(|| {
+				let res = System::set_code(
+					RawOrigin::Root.into(),
+					vec![1, 2, 3, 4],
+				);
+
+				assert_eq!(expected.map_err(DispatchError::from), res);
+			});
+		}
+	}
+
+	#[test]
+	fn set_code_with_real_wasm_blob() {
+		let executor = substrate_test_runtime_client::new_native_executor();
+		let mut ext = new_test_ext();
+		ext.register_extension(sp_core::traits::CallInWasmExt::new(executor));
+		ext.execute_with(|| {
+			System::set_code(
+				RawOrigin::Root.into(),
+				substrate_test_runtime_client::runtime::WASM_BINARY.to_vec(),
+			).unwrap();
+		});
+	}
 }
diff --git a/frame/transaction-payment/src/lib.rs b/frame/transaction-payment/src/lib.rs
index bae3096f3cdd1..00dbf6bc66b73 100644
--- a/frame/transaction-payment/src/lib.rs
+++ b/frame/transaction-payment/src/lib.rs
@@ -151,7 +151,7 @@ impl<T: Trait + Send + Sync> ChargeTransactionPayment<T> {
 	///      transactions can have a tip.
 	///
 	/// final_fee = base_fee + targeted_fee_adjustment(len_fee + weight_fee) + tip;
-	fn compute_fee(
+	pub fn compute_fee(
 		len: u32,
 		info: <Self as SignedExtension>::DispatchInfo,
 		tip: BalanceOf<T>,
@@ -218,20 +218,23 @@ impl<T: Trait + Send + Sync> SignedExtension for ChargeTransactionPayment<T>
 		// pay any fees.
 		let tip = self.0;
 		let fee = Self::compute_fee(len as u32, info, tip);
-		let imbalance = match T::Currency::withdraw(
-			who,
-			fee,
-			if tip.is_zero() {
-				WithdrawReason::TransactionPayment.into()
-			} else {
-				WithdrawReason::TransactionPayment | WithdrawReason::Tip
-			},
-			ExistenceRequirement::KeepAlive,
-		) {
-			Ok(imbalance) => imbalance,
-			Err(_) => return InvalidTransaction::Payment.into(),
-		};
-		T::OnTransactionPayment::on_unbalanced(imbalance);
+		// Only mess with balances if fee is not zero.
+		if !fee.is_zero() {
+			let imbalance = match T::Currency::withdraw(
+				who,
+				fee,
+				if tip.is_zero() {
+					WithdrawReason::TransactionPayment.into()
+				} else {
+					WithdrawReason::TransactionPayment | WithdrawReason::Tip
+				},
+				ExistenceRequirement::KeepAlive,
+			) {
+				Ok(imbalance) => imbalance,
+				Err(_) => return InvalidTransaction::Payment.into(),
+			};
+			T::OnTransactionPayment::on_unbalanced(imbalance);
+		}
 
 		let mut r = ValidTransaction::default();
 		// NOTE: we probably want to maximize the _fee (of any type) per weight unit_ here, which
diff --git a/primitives/api/Cargo.toml b/primitives/api/Cargo.toml
index 1e3e555456000..b9f736570ac4d 100644
--- a/primitives/api/Cargo.toml
+++ b/primitives/api/Cargo.toml
@@ -11,7 +11,7 @@ sp-core = { version = "2.0.0", default-features = false, path = "../core" }
 sp-std = { version = "2.0.0", default-features = false, path = "../std" }
 sp-runtime = { version = "2.0.0", default-features = false, path = "../runtime" }
 sp-version = { version = "2.0.0", default-features = false, path = "../version" }
-sp-state-machine = { version = "2.0.0", optional = true, path = "../../primitives/state-machine" }
+sp-state-machine = { version = "0.8", optional = true, path = "../../primitives/state-machine" }
 hash-db = { version = "0.15.2", optional = true }
 
 [dev-dependencies]
diff --git a/primitives/api/proc-macro/src/impl_runtime_apis.rs b/primitives/api/proc-macro/src/impl_runtime_apis.rs
index dc4031fbc4b8a..770a843bfa6c1 100644
--- a/primitives/api/proc-macro/src/impl_runtime_apis.rs
+++ b/primitives/api/proc-macro/src/impl_runtime_apis.rs
@@ -323,12 +323,13 @@ fn generate_runtime_api_base_structures() -> Result<TokenStream> {
 					})
 			}
 
-			fn into_storage_changes<
-				T: #crate_::ChangesTrieStorage<#crate_::HasherFor<Block>, #crate_::NumberFor<Block>>
-			>(
+			fn into_storage_changes(
 				&self,
 				backend: &Self::StateBackend,
-				changes_trie_storage: Option<&T>,
+				changes_trie_state: Option<&#crate_::ChangesTrieState<
+					#crate_::HasherFor<Block>,
+					#crate_::NumberFor<Block>,
+				>>,
 				parent_hash: Block::Hash,
 			) -> std::result::Result<
 				#crate_::StorageChanges<Self::StateBackend, Block>,
@@ -337,7 +338,7 @@ fn generate_runtime_api_base_structures() -> Result<TokenStream> {
 				self.initialized_block.borrow_mut().take();
 				self.changes.replace(Default::default()).into_storage_changes(
 					backend,
-					changes_trie_storage,
+					changes_trie_state,
 					parent_hash,
 					self.storage_transaction_cache.replace(Default::default()),
 				)
diff --git a/primitives/api/src/lib.rs b/primitives/api/src/lib.rs
index 122e863228966..bde00d48172e8 100644
--- a/primitives/api/src/lib.rs
+++ b/primitives/api/src/lib.rs
@@ -36,7 +36,7 @@ extern crate self as sp_api;
 #[doc(hidden)]
 #[cfg(feature = "std")]
 pub use sp_state_machine::{
-	OverlayedChanges, StorageProof, Backend as StateBackend, ChangesTrieStorage,
+	OverlayedChanges, StorageProof, Backend as StateBackend, ChangesTrieState,
 };
 #[doc(hidden)]
 #[cfg(feature = "std")]
@@ -325,10 +325,10 @@ pub trait ApiExt<Block: BlockT>: ApiErrorExt {
 	/// api functions.
 	///
 	/// After executing this function, all collected changes are reset.
-	fn into_storage_changes<T: ChangesTrieStorage<HasherFor<Block>, NumberFor<Block>>>(
+	fn into_storage_changes(
 		&self,
 		backend: &Self::StateBackend,
-		changes_trie_storage: Option<&T>,
+		changes_trie_state: Option<&ChangesTrieState<HasherFor<Block>, NumberFor<Block>>>,
 		parent_hash: Block::Hash,
 	) -> Result<StorageChanges<Self::StateBackend, Block>, String> where Self: Sized;
 }
diff --git a/primitives/api/test/Cargo.toml b/primitives/api/test/Cargo.toml
index f1f0dfb50f12b..5892063bd1fc4 100644
--- a/primitives/api/test/Cargo.toml
+++ b/primitives/api/test/Cargo.toml
@@ -12,7 +12,7 @@ sp-runtime = { version = "2.0.0", path = "../../runtime" }
 sp-blockchain = { version = "2.0.0", path = "../../blockchain" }
 sp-consensus = { version = "0.8", path = "../../../primitives/consensus/common" }
 codec = { package = "parity-scale-codec", version = "1.0.0" }
-sp-state-machine = { version = "2.0.0", path = "../../../primitives/state-machine" }
+sp-state-machine = { version = "0.8", path = "../../../primitives/state-machine" }
 trybuild = "1.0.17"
 rustversion = "1.0.0"
 
diff --git a/primitives/api/test/tests/runtime_calls.rs b/primitives/api/test/tests/runtime_calls.rs
index f45df7c517254..66412edae026d 100644
--- a/primitives/api/test/tests/runtime_calls.rs
+++ b/primitives/api/test/tests/runtime_calls.rs
@@ -185,7 +185,7 @@ fn record_proof_works() {
 	// Use the proof backend to execute `execute_block`.
 	let mut overlay = Default::default();
 	let executor = NativeExecutor::<LocalExecutor>::new(WasmExecutionMethod::Interpreted, None);
-	execution_proof_check_on_trie_backend(
+	execution_proof_check_on_trie_backend::<_, u64, _>(
 		&backend,
 		&mut overlay,
 		&executor,
diff --git a/primitives/blockchain/Cargo.toml b/primitives/blockchain/Cargo.toml
index 4f3f0d0b5fad0..a3c442094daaf 100644
--- a/primitives/blockchain/Cargo.toml
+++ b/primitives/blockchain/Cargo.toml
@@ -13,4 +13,4 @@ codec = { package = "parity-scale-codec", version = "1.0.0", default-features =
 sp-consensus = { version = "0.8", path = "../consensus/common" }
 sp-runtime = { version = "2.0.0", path = "../runtime" }
 sp-block-builder = { version = "2.0.0", path = "../block-builder" }
-sp-state-machine = { version = "2.0.0", path = "../state-machine" }
+sp-state-machine = { version = "0.8", path = "../state-machine" }
diff --git a/primitives/blockchain/src/backend.rs b/primitives/blockchain/src/backend.rs
index 8571d76801079..101dcd1443d6b 100644
--- a/primitives/blockchain/src/backend.rs
+++ b/primitives/blockchain/src/backend.rs
@@ -228,11 +228,13 @@ pub trait Cache<Block: BlockT>: Send + Sync {
 	/// Returns cached value by the given key.
 	///
 	/// Returned tuple is the range where value has been active and the value itself.
+	/// Fails if read from cache storage fails or if the value for block is discarded
+	/// (i.e. if block is earlier that best finalized, but it is not in canonical chain).
 	fn get_at(
 		&self,
 		key: &well_known_cache_keys::Id,
 		block: &BlockId<Block>,
-	) -> Option<((NumberFor<Block>, Block::Hash), Option<(NumberFor<Block>, Block::Hash)>, Vec<u8>)>;
+	) -> Result<Option<((NumberFor<Block>, Block::Hash), Option<(NumberFor<Block>, Block::Hash)>, Vec<u8>)>>;
 }
 
 /// Blockchain info
diff --git a/primitives/blockchain/src/error.rs b/primitives/blockchain/src/error.rs
index dbab93738e79f..d51ab787c72fb 100644
--- a/primitives/blockchain/src/error.rs
+++ b/primitives/blockchain/src/error.rs
@@ -106,6 +106,9 @@ pub enum Error {
 	/// Changes tries are not supported.
 	#[display(fmt = "Changes tries are not supported by the runtime")]
 	ChangesTriesNotSupported,
+	/// Error reading changes tries configuration.
+	#[display(fmt = "Error reading changes tries configuration")]
+	ErrorReadingChangesTriesConfig,
 	/// Key changes query has failed.
 	#[display(fmt = "Failed to check changes proof: {}", _0)]
 	#[from(ignore)]
diff --git a/primitives/consensus/common/Cargo.toml b/primitives/consensus/common/Cargo.toml
index 4c38e31914700..3ae79caa43126 100644
--- a/primitives/consensus/common/Cargo.toml
+++ b/primitives/consensus/common/Cargo.toml
@@ -11,7 +11,7 @@ libp2p = { version = "0.14.0-alpha.1", default-features = false }
 log = "0.4.8"
 sp-core = { path= "../../core" }
 sp-inherents = { version = "2.0.0", path = "../../inherents" }
-sp-state-machine = { version = "2.0.0", path = "../../../primitives/state-machine" }
+sp-state-machine = { version = "0.8.0", path = "../../../primitives/state-machine" }
 futures = { version = "0.3.1", features = ["thread-pool"] }
 futures-timer = "0.4.0"
 sp-std = { version = "2.0.0", path = "../../std" }
diff --git a/primitives/consensus/common/src/lib.rs b/primitives/consensus/common/src/lib.rs
index 1b98ede376857..4927faede06f7 100644
--- a/primitives/consensus/common/src/lib.rs
+++ b/primitives/consensus/common/src/lib.rs
@@ -74,13 +74,16 @@ pub enum BlockStatus {
 /// Environment producer for a Consensus instance. Creates proposer instance and communication streams.
 pub trait Environment<B: BlockT> {
 	/// The proposer type this creates.
-	type Proposer: Proposer<B> + 'static;
+	type Proposer: Proposer<B> + Send + 'static;
+	/// A future that resolves to the proposer.
+	type CreateProposer: Future<Output = Result<Self::Proposer, Self::Error>>
+		+ Send + Unpin + 'static;
 	/// Error which can occur upon creation.
 	type Error: From<Error> + std::fmt::Debug + 'static;
 
 	/// Initialize the proposal logic on top of a specific header. Provide
 	/// the authorities at that header.
-	fn init(&mut self, parent_header: &B::Header) -> Result<Self::Proposer, Self::Error>;
+	fn init(&mut self, parent_header: &B::Header) -> Self::CreateProposer;
 }
 
 /// A proposal that is created by a [`Proposer`].
diff --git a/primitives/core/Cargo.toml b/primitives/core/Cargo.toml
index 8242ff8044466..f7eec82e55daf 100644
--- a/primitives/core/Cargo.toml
+++ b/primitives/core/Cargo.toml
@@ -26,7 +26,7 @@ zeroize = { version = "1.0.0", default-features = false }
 lazy_static = { version = "1.4.0", default-features = false, optional = true }
 parking_lot = { version = "0.9.0", optional = true }
 sp-debug-derive = { version = "2.0.0", path = "../debug-derive" }
-sp-externalities = { version = "2.0.0", optional = true, path = "../externalities" }
+sp-externalities = { version = "0.8.0", optional = true, path = "../externalities" }
 sp-storage = { version = "2.0.0", default-features = false, path = "../storage" }
 libsecp256k1 = { version = "0.3.2", default-features = false }
 
diff --git a/primitives/core/src/changes_trie.rs b/primitives/core/src/changes_trie.rs
index 65619a9d45315..d38761ccf0fd1 100644
--- a/primitives/core/src/changes_trie.rs
+++ b/primitives/core/src/changes_trie.rs
@@ -38,6 +38,17 @@ pub struct ChangesTrieConfiguration {
 	pub digest_levels: u32,
 }
 
+/// Substrate changes trie configuration range.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct ChangesTrieConfigurationRange<Number, Hash> {
+	/// Zero block of configuration.
+	pub zero: (Number, Hash),
+	/// Last block of configuration (if configuration has been deactivated at some point).
+	pub end: Option<(Number, Hash)>,
+	/// The configuration itself. None if changes tries were disabled in this range.
+	pub config: Option<ChangesTrieConfiguration>,
+}
+
 impl ChangesTrieConfiguration {
 	/// Create new configuration given digest interval and levels.
 	pub fn new(digest_interval: u32, digest_levels: u32) -> Self {
diff --git a/primitives/core/src/lib.rs b/primitives/core/src/lib.rs
index 32e65de40dbaa..ee768ee4a6226 100644
--- a/primitives/core/src/lib.rs
+++ b/primitives/core/src/lib.rs
@@ -75,7 +75,7 @@ mod tests;
 
 pub use self::hash::{H160, H256, H512, convert_hash};
 pub use self::uint::U256;
-pub use changes_trie::ChangesTrieConfiguration;
+pub use changes_trie::{ChangesTrieConfiguration, ChangesTrieConfigurationRange};
 #[cfg(feature = "full_crypto")]
 pub use crypto::{DeriveJunction, Pair, Public};
 
diff --git a/primitives/core/src/traits.rs b/primitives/core/src/traits.rs
index cd188e3367707..020b5e2dc5461 100644
--- a/primitives/core/src/traits.rs
+++ b/primitives/core/src/traits.rs
@@ -80,7 +80,7 @@ sp_externalities::decl_extension! {
 }
 
 /// Code execution engine.
-pub trait CodeExecutor: Sized + Send + Sync {
+pub trait CodeExecutor: Sized + Send + Sync + CallInWasm + Clone + 'static {
 	/// Externalities error type.
 	type Error: Display + Debug + Send + 'static;
 
@@ -99,3 +99,30 @@ pub trait CodeExecutor: Sized + Send + Sync {
 		native_call: Option<NC>,
 	) -> (Result<crate::NativeOrEncoded<R>, Self::Error>, bool);
 }
+
+/// Something that can call a method in a WASM blob.
+pub trait CallInWasm: Send + Sync {
+	/// Call the given `method` in the given `wasm_blob` using `call_data` (SCALE encoded arguments)
+	/// to decode the arguments for the method.
+	///
+	/// Returns the SCALE encoded return value of the method.
+	fn call_in_wasm(
+		&self,
+		wasm_blob: &[u8],
+		method: &str,
+		call_data: &[u8],
+		ext: &mut dyn Externalities,
+	) -> Result<Vec<u8>, String>;
+}
+
+sp_externalities::decl_extension! {
+	/// The call-in-wasm extension to register/retrieve from the externalities.
+	pub struct CallInWasmExt(Box<dyn CallInWasm>);
+}
+
+impl CallInWasmExt {
+	/// Creates a new instance of `Self`.
+	pub fn new<T: CallInWasm + 'static>(inner: T) -> Self {
+		Self(Box::new(inner))
+	}
+}
diff --git a/primitives/externalities/Cargo.toml b/primitives/externalities/Cargo.toml
index 09ce3253f2d98..23889da4ea289 100644
--- a/primitives/externalities/Cargo.toml
+++ b/primitives/externalities/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "sp-externalities"
-version = "2.0.0"
+version = "0.8.0"
 license = "GPL-3.0"
 authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2018"
@@ -8,4 +8,4 @@ edition = "2018"
 [dependencies]
 sp-storage = { version = "2.0.0", path = "../storage" }
 sp-std = { version = "2.0.0", path = "../std" }
-environmental = { version = "1.0.2" }
+environmental = { version = "1.1.1" }
diff --git a/primitives/io/Cargo.toml b/primitives/io/Cargo.toml
index 04350c9479ede..2f03f230ef8e0 100644
--- a/primitives/io/Cargo.toml
+++ b/primitives/io/Cargo.toml
@@ -10,10 +10,10 @@ hash-db = { version = "0.15.2", default-features = false }
 sp-core = { version = "2.0.0", default-features = false, path = "../core" }
 sp-std = { version = "2.0.0", default-features = false, path = "../std" }
 libsecp256k1 = { version = "0.3.4", optional = true }
-sp-state-machine = { version = "2.0.0", optional = true, path = "../../primitives/state-machine" }
+sp-state-machine = { version = "0.8", optional = true, path = "../../primitives/state-machine" }
 sp-runtime-interface = { version = "2.0.0", default-features = false, path = "../runtime-interface" }
 sp-trie = { version = "2.0.0", optional = true, path = "../../primitives/trie" }
-sp-externalities = { version = "2.0.0", optional = true, path = "../externalities" }
+sp-externalities = { version = "0.8.0", optional = true, path = "../externalities" }
 log = { version = "0.4.8", optional = true }
 
 [features]
diff --git a/primitives/io/src/lib.rs b/primitives/io/src/lib.rs
index 7ac2ae1012272..704477b1fb2bc 100644
--- a/primitives/io/src/lib.rs
+++ b/primitives/io/src/lib.rs
@@ -35,7 +35,7 @@ use sp_std::ops::Deref;
 #[cfg(feature = "std")]
 use sp_core::{
 	crypto::Pair,
-	traits::KeystoreExt,
+	traits::{KeystoreExt, CallInWasmExt},
 	offchain::{OffchainExt, TransactionPoolExt},
 	hexdisplay::HexDisplay,
 	storage::{ChildStorageKey, ChildInfo},
@@ -49,7 +49,7 @@ use sp_core::{
 };
 
 #[cfg(feature = "std")]
-use ::sp_trie::{TrieConfiguration, trie_types::Layout};
+use sp_trie::{TrieConfiguration, trie_types::Layout};
 
 use sp_runtime_interface::{runtime_interface, Pointer};
 
@@ -351,6 +351,25 @@ pub trait Misc {
 	fn print_hex(data: &[u8]) {
 		log::debug!(target: "runtime", "{}", HexDisplay::from(&data));
 	}
+
+	/// Extract the runtime version of the given wasm blob by calling `Core_version`.
+	///
+	/// Returns the SCALE encoded runtime version and `None` if the call failed.
+	///
+	/// # Performance
+	///
+	/// Calling this function is very expensive and should only be done very occasionally.
+	/// For getting the runtime version, it requires instantiating the wasm blob and calling a
+	/// function in this blob.
+	fn runtime_version(&mut self, wasm: &[u8]) -> Option<Vec<u8>> {
+		// Create some dummy externalities, `Core_version` should not write data anyway.
+		let mut ext = sp_state_machine::BasicExternalities::default();
+
+		self.extension::<CallInWasmExt>()
+			.expect("No `CallInWasmExt` associated for the current context!")
+			.call_in_wasm(wasm, "Core_version", &[], &mut ext)
+			.ok()
+	}
 }
 
 /// Interfaces for working with crypto related types from within the runtime.
diff --git a/primitives/runtime-interface/Cargo.toml b/primitives/runtime-interface/Cargo.toml
index cdc94b6a2f226..7ed2257556b47 100644
--- a/primitives/runtime-interface/Cargo.toml
+++ b/primitives/runtime-interface/Cargo.toml
@@ -8,15 +8,14 @@ edition = "2018"
 sp-wasm-interface = { version = "2.0.0", optional = true, path = "../wasm-interface" }
 sp-std = { version = "2.0.0", default-features = false, path = "../std" }
 sp-runtime-interface-proc-macro = { version = "2.0.0", path = "proc-macro" }
-sp-externalities = { version = "2.0.0", optional = true, path = "../externalities" }
+sp-externalities = { version = "0.8.0", optional = true, path = "../externalities" }
 codec = { package = "parity-scale-codec", version = "1.0.6", default-features = false }
-environmental = { version = "1.0.2", optional = true }
 static_assertions = "1.0.0"
 primitive-types = { version = "0.6.1", default-features = false }
 
 [dev-dependencies]
 sp-runtime-interface-test-wasm = { version = "2.0.0", path = "test-wasm" }
-sp-state-machine = { version = "2.0.0", path = "../../primitives/state-machine" }
+sp-state-machine = { version = "0.8", path = "../../primitives/state-machine" }
 sp-core = { version = "2.0.0", path = "../core" }
 sp-io = { version = "2.0.0", path = "../io" }
 rustversion = "1.0.0"
@@ -29,7 +28,6 @@ std = [
 	"sp-std/std",
 	"codec/std",
 	"sp-externalities",
-	"environmental",
 	"primitive-types/std",
 ]
 
diff --git a/primitives/runtime-interface/proc-macro/src/runtime_interface/bare_function_interface.rs b/primitives/runtime-interface/proc-macro/src/runtime_interface/bare_function_interface.rs
index 55b5eb3a4d616..bdddc5eba70e7 100644
--- a/primitives/runtime-interface/proc-macro/src/runtime_interface/bare_function_interface.rs
+++ b/primitives/runtime-interface/proc-macro/src/runtime_interface/bare_function_interface.rs
@@ -21,10 +21,10 @@
 //! functions will prepare the parameters for the FFI boundary, call the external host function
 //! exported into wasm and convert back the result.
 //!
-//! [`generate`](bare_function_interface::generate) is the entry point for generating for each
+//! [`generate`] is the entry point for generating for each
 //! trait method one bare function.
 //!
-//! [`function_for_method`](bare_function_interface::function_for_method) generates the bare
+//! [`function_for_method`] generates the bare
 //! function per trait method. Each bare function contains both implementations. The implementations
 //! are feature-gated, so that one is compiled for the native and the other for the wasm side.
 
diff --git a/primitives/runtime-interface/src/host.rs b/primitives/runtime-interface/src/host.rs
index 2fc272165f33c..cf03e6623af59 100644
--- a/primitives/runtime-interface/src/host.rs
+++ b/primitives/runtime-interface/src/host.rs
@@ -49,6 +49,9 @@ pub trait IntoPreallocatedFFIValue: RIType {
 }
 
 /// Something that can be created from a ffi value.
+/// Implementations are safe to assume that the `arg` given to `from_ffi_value`
+/// is only generated by the corresponding [`wasm::IntoFFIValue`](crate::wasm::IntoFFIValue)
+/// implementation.
 pub trait FromFFIValue: RIType {
 	/// As `Self` can be an unsized type, it needs to be represented by a sized type at the host.
 	/// This `SelfInstance` is the sized type.
diff --git a/primitives/runtime-interface/src/impls.rs b/primitives/runtime-interface/src/impls.rs
index 23be7fd35adfc..3cd114268bbd3 100644
--- a/primitives/runtime-interface/src/impls.rs
+++ b/primitives/runtime-interface/src/impls.rs
@@ -150,7 +150,7 @@ impl IntoFFIValue for bool {
 ///
 /// The `u64` value is build by `length 32bit << 32 | pointer 32bit`
 ///
-/// If `T == u8` the length and the pointer are taken directly from the `Self`.
+/// If `T == u8` the length and the pointer are taken directly from `Self`.
 /// Otherwise `Self` is encoded and the length and the pointer are taken from the encoded vector.
 impl<T> RIType for Vec<T> {
 	type FFIType = u64;
@@ -209,7 +209,7 @@ impl<T: 'static + Decode> FromFFIValue for Vec<T> {
 ///
 /// The `u64` value is build by `length 32bit << 32 | pointer 32bit`
 ///
-/// If `T == u8` the length and the pointer are taken directly from the `Self`.
+/// If `T == u8` the length and the pointer are taken directly from `Self`.
 /// Otherwise `Self` is encoded and the length and the pointer are taken from the encoded vector.
 impl<T> RIType for [T] {
 	type FFIType = u64;
@@ -400,7 +400,7 @@ for_primitive_types! {
 ///
 /// The `u64` value is build by `length 32bit << 32 | pointer 32bit`
 ///
-/// The length and the pointer are taken directly from the `Self`.
+/// The length and the pointer are taken directly from `Self`.
 impl RIType for str {
 	type FFIType = u64;
 }
diff --git a/primitives/runtime-interface/src/lib.rs b/primitives/runtime-interface/src/lib.rs
index 330b1699a609f..30d74ad2db399 100644
--- a/primitives/runtime-interface/src/lib.rs
+++ b/primitives/runtime-interface/src/lib.rs
@@ -25,10 +25,10 @@
 //! # Using a type in a runtime interface
 //!
 //! Any type that should be used in a runtime interface as argument or return value needs to
-//! implement [`RIType`]. The associated type `FFIType` is the type that is used in the FFI
-//! function to represent the actual type. For example `[T]` is represented by an `u64`. The slice
-//! pointer and the length will be mapped to an `u64` value. For more information, see the
-//! implementation of [`RIType`] for [`T`]. The FFI function definition is used when calling from
+//! implement [`RIType`]. The associated type [`FFIType`](RIType::FFIType) is the type that is used
+//! in the FFI function to represent the actual type. For example `[T]` is represented by an `u64`.
+//! The slice pointer and the length will be mapped to an `u64` value. For more information see
+//! this [table](#ffi-type-and-conversion). The FFI function definition is used when calling from
 //! the wasm runtime into the node.
 //!
 //! Traits are used to convert from a type to the corresponding [`RIType::FFIType`].
@@ -69,6 +69,34 @@
 //!
 //! For more information on declaring a runtime interface, see
 //! [`#[runtime_interface]`](attr.runtime_interface.html).
+//!
+//! # FFI type and conversion
+//!
+//! The following table documents how values of types are passed between the wasm and
+//! the host side and how they are converted into the corresponding type.
+//!
+//! | Type | FFI type | Conversion |
+//! |----|----|----|
+//! | `u8` | `u8` | `Identity` |
+//! | `u16` | `u16` | `Identity` |
+//! | `u32` | `u32` | `Identity` |
+//! | `u64` | `u64` | `Identity` |
+//! | `i8` | `i8` | `Identity` |
+//! | `i16` | `i16` | `Identity` |
+//! | `i32` | `i32` | `Identity` |
+//! | `i64` | `i64` | `Identity` |
+//! | `bool` | `u8` | `if v { 1 } else { 0 }` |
+//! | `&str` | `u64` | <code>v.len() 32bit << 32 &#124; v.as_ptr() 32bit</code> |
+//! | `&[u8]` | `u64` | <code>v.len() 32bit << 32 &#124; v.as_ptr() 32bit</code> |
+//! | `Vec<u8>` | `u64` | <code>v.len() 32bit << 32 &#124; v.as_ptr() 32bit</code> |
+//! | `Vec<T> where T: Encode` | `u64` | `let e = v.encode();`<br><br><code>e.len() 32bit << 32 &#124; e.as_ptr() 32bit</code> |
+//! | `&[T] where T: Encode` | `u64` | `let e = v.encode();`<br><br><code>e.len() 32bit << 32 &#124; e.as_ptr() 32bit</code> |
+//! | `[u8; N]` | `u32` | `v.as_ptr()` |
+//! | `*const T` | `u32` | `Identity` |
+//! | [`T where T: PassBy<PassBy=Inner>`](pass_by::Inner) | Depends on inner | Depends on inner |
+//! | [`T where T: PassBy<PassBy=Codec>`](pass_by::Codec) | `u64`| <code>v.len() 32bit << 32 &#124; v.as_ptr() 32bit</code> |
+//!
+//! `Identity` means that the value is converted directly into the corresponding FFI type.
 
 #![cfg_attr(not(feature = "std"), no_std)]
 
@@ -237,7 +265,7 @@ pub use codec;
 pub(crate) mod impls;
 #[cfg(feature = "std")]
 pub mod host;
-#[cfg(not(feature = "std"))]
+#[cfg(any(not(feature = "std"), doc))]
 pub mod wasm;
 pub mod pass_by;
 
diff --git a/primitives/runtime-interface/src/pass_by.rs b/primitives/runtime-interface/src/pass_by.rs
index 81da2fe7e6a3a..597a0284eee2a 100644
--- a/primitives/runtime-interface/src/pass_by.rs
+++ b/primitives/runtime-interface/src/pass_by.rs
@@ -14,11 +14,10 @@
 // You should have received a copy of the GNU General Public License
 // along with Substrate.  If not, see <http://www.gnu.org/licenses/>.
 
-//! Provides the [`PassBy`](pass_by::PassBy) trait to simplify the implementation of the
+//! Provides the [`PassBy`](PassBy) trait to simplify the implementation of the
 //! runtime interface traits for custom types.
 //!
-//! [`Codec`](pass_by::Codec), [`Inner`](pass_by::Inner) and [`Enum`](pass_by::Enum) are the
-//! provided strategy implementations.
+//! [`Codec`], [`Inner`] and [`Enum`] are the provided strategy implementations.
 
 use crate::{RIType, util::{unpack_ptr_and_len, pack_ptr_and_len}};
 
diff --git a/primitives/runtime-interface/src/wasm.rs b/primitives/runtime-interface/src/wasm.rs
index 476dfb8a4ce5a..a0801c2bfb5a9 100644
--- a/primitives/runtime-interface/src/wasm.rs
+++ b/primitives/runtime-interface/src/wasm.rs
@@ -26,7 +26,8 @@ use sp_std::cell::Cell;
 ///
 /// It is unsafe behavior to call `Something::into_ffi_value().get()` and take this as input for
 /// `from_ffi_value`. Implementations are safe to assume that the `arg` given to `from_ffi_value`
-/// is only generated by the corresponding `host::IntoFFIValue` implementation.
+/// is only generated by the corresponding [`host::IntoFFIValue`](crate::host::IntoFFIValue)
+/// implementation.
 pub trait FromFFIValue: Sized + RIType {
 	/// Create `Self` from the given ffi value.
 	fn from_ffi_value(arg: Self::FFIType) -> Self;
diff --git a/primitives/runtime-interface/test/Cargo.toml b/primitives/runtime-interface/test/Cargo.toml
index 35eb8cb8e1f56..f0a4c0edd4a53 100644
--- a/primitives/runtime-interface/test/Cargo.toml
+++ b/primitives/runtime-interface/test/Cargo.toml
@@ -7,8 +7,8 @@ publish = false
 
 [dependencies]
 sp-runtime-interface = { version = "2.0.0", path = "../" }
-sc-executor = { version = "2.0.0", path = "../../../client/executor" }
+sc-executor = { version = "0.8", path = "../../../client/executor" }
 sp-runtime-interface-test-wasm = { version = "2.0.0", path = "../test-wasm" }
-sp-state-machine = { version = "2.0.0", path = "../../../primitives/state-machine" }
+sp-state-machine = { version = "0.8", path = "../../../primitives/state-machine" }
 sp-core = { version = "2.0.0", path = "../../core" }
 sp-io = { version = "2.0.0", path = "../../io" }
diff --git a/primitives/runtime-interface/test/src/lib.rs b/primitives/runtime-interface/test/src/lib.rs
index 3cfb589b05519..b209e1f71ce55 100644
--- a/primitives/runtime-interface/test/src/lib.rs
+++ b/primitives/runtime-interface/test/src/lib.rs
@@ -30,7 +30,6 @@ fn call_wasm_method<HF: HostFunctionsT>(method: &str) -> TestExternalities {
 	let mut ext_ext = ext.ext();
 
 	sc_executor::call_in_wasm::<
-		_,
 		(
 			HF,
 			sp_io::SubstrateHostFunctions,
diff --git a/primitives/runtime/src/generic/digest.rs b/primitives/runtime/src/generic/digest.rs
index 6653cfb8a86b3..fef02d4f00959 100644
--- a/primitives/runtime/src/generic/digest.rs
+++ b/primitives/runtime/src/generic/digest.rs
@@ -23,7 +23,7 @@ use sp_std::prelude::*;
 
 use crate::ConsensusEngineId;
 use crate::codec::{Decode, Encode, Input, Error};
-use sp_core::RuntimeDebug;
+use sp_core::{ChangesTrieConfiguration, RuntimeDebug};
 
 /// Generic header digest.
 #[derive(PartialEq, Eq, Clone, Encode, Decode, RuntimeDebug)]
@@ -97,10 +97,32 @@ pub enum DigestItem<Hash> {
 	/// by runtimes.
 	Seal(ConsensusEngineId, Vec<u8>),
 
+	/// Digest item that contains signal from changes tries manager to the
+	/// native code.
+	ChangesTrieSignal(ChangesTrieSignal),
+
 	/// Some other thing. Unsupported and experimental.
 	Other(Vec<u8>),
 }
 
+/// Available changes trie signals.
+#[derive(PartialEq, Eq, Clone, Encode, Decode)]
+#[cfg_attr(feature = "std", derive(Debug))]
+pub enum ChangesTrieSignal {
+	/// New changes trie configuration is enacted, starting from **next block**.
+	///
+	/// The block that emits this signal will contain changes trie (CT) that covers
+	/// blocks range [BEGIN; current block], where BEGIN is (order matters):
+	/// - LAST_TOP_LEVEL_DIGEST_BLOCK+1 if top level digest CT has ever been created
+	///   using current configuration AND the last top level digest CT has been created
+	///   at block LAST_TOP_LEVEL_DIGEST_BLOCK;
+	/// - LAST_CONFIGURATION_CHANGE_BLOCK+1 if there has been CT configuration change
+	///   before and the last configuration change happened at block
+	///   LAST_CONFIGURATION_CHANGE_BLOCK;
+	/// - 1 otherwise.
+	NewConfiguration(Option<ChangesTrieConfiguration>),
+}
+
 #[cfg(feature = "std")]
 impl<Hash: Encode> serde::Serialize for DigestItem<Hash> {
 	fn serialize<S>(&self, seq: S) -> Result<S::Ok, S::Error> where S: serde::Serializer {
@@ -141,6 +163,9 @@ pub enum DigestItemRef<'a, Hash: 'a> {
 	/// Put a Seal on it. This is only used by native code, and is never seen
 	/// by runtimes.
 	Seal(&'a ConsensusEngineId, &'a Vec<u8>),
+	/// Digest item that contains signal from changes tries manager to the
+	/// native code.
+	ChangesTrieSignal(&'a ChangesTrieSignal),
 	/// Any 'non-system' digest item, opaque to the native code.
 	Other(&'a Vec<u8>),
 }
@@ -152,11 +177,12 @@ pub enum DigestItemRef<'a, Hash: 'a> {
 #[repr(u32)]
 #[derive(Encode, Decode)]
 pub enum DigestItemType {
+	Other = 0,
 	ChangesTrieRoot = 2,
-	PreRuntime = 6,
 	Consensus = 4,
 	Seal = 5,
-	Other = 0,
+	PreRuntime = 6,
+	ChangesTrieSignal = 7,
 }
 
 /// Type of a digest item that contains raw data; this also names the consensus engine ID where
@@ -181,6 +207,7 @@ impl<Hash> DigestItem<Hash> {
 			DigestItem::PreRuntime(ref v, ref s) => DigestItemRef::PreRuntime(v, s),
 			DigestItem::Consensus(ref v, ref s) => DigestItemRef::Consensus(v, s),
 			DigestItem::Seal(ref v, ref s) => DigestItemRef::Seal(v, s),
+			DigestItem::ChangesTrieSignal(ref s) => DigestItemRef::ChangesTrieSignal(s),
 			DigestItem::Other(ref v) => DigestItemRef::Other(v),
 		}
 	}
@@ -205,6 +232,11 @@ impl<Hash> DigestItem<Hash> {
 		self.dref().as_seal()
 	}
 
+	/// Returns `Some` if the entry is the `ChangesTrieSignal` entry.
+	pub fn as_changes_trie_signal(&self) -> Option<&ChangesTrieSignal> {
+		self.dref().as_changes_trie_signal()
+	}
+
 	/// Returns Some if `self` is a `DigestItem::Other`.
 	pub fn as_other(&self) -> Option<&[u8]> {
 		match *self {
@@ -253,6 +285,9 @@ impl<Hash: Decode> Decode for DigestItem<Hash> {
 				let vals: (ConsensusEngineId, Vec<u8>) = Decode::decode(input)?;
 				Ok(DigestItem::Seal(vals.0, vals.1))
 			},
+			DigestItemType::ChangesTrieSignal => Ok(DigestItem::ChangesTrieSignal(
+				Decode::decode(input)?,
+			)),
 			DigestItemType::Other => Ok(DigestItem::Other(
 				Decode::decode(input)?,
 			)),
@@ -293,6 +328,14 @@ impl<'a, Hash> DigestItemRef<'a, Hash> {
 		}
 	}
 
+	/// Cast this digest item into `ChangesTrieSignal`.
+	pub fn as_changes_trie_signal(&self) -> Option<&'a ChangesTrieSignal> {
+		match *self {
+			DigestItemRef::ChangesTrieSignal(ref changes_trie_signal) => Some(changes_trie_signal),
+			_ => None,
+		}
+	}
+
 	/// Cast this digest item into `PreRuntime`
 	pub fn as_other(&self) -> Option<&'a [u8]> {
 		match *self {
@@ -342,6 +385,10 @@ impl<'a, Hash: Encode> Encode for DigestItemRef<'a, Hash> {
 				DigestItemType::PreRuntime.encode_to(&mut v);
 				(val, data).encode_to(&mut v);
 			},
+			DigestItemRef::ChangesTrieSignal(changes_trie_signal) => {
+				DigestItemType::ChangesTrieSignal.encode_to(&mut v);
+				changes_trie_signal.encode_to(&mut v);
+			},
 			DigestItemRef::Other(val) => {
 				DigestItemType::Other.encode_to(&mut v);
 				val.encode_to(&mut v);
@@ -352,6 +399,15 @@ impl<'a, Hash: Encode> Encode for DigestItemRef<'a, Hash> {
 	}
 }
 
+impl ChangesTrieSignal {
+	/// Try to cast this signal to NewConfiguration.
+	pub fn as_new_configuration(&self) -> Option<&Option<ChangesTrieConfiguration>> {
+		match self {
+			ChangesTrieSignal::NewConfiguration(config) => Some(config),
+		}
+	}
+}
+
 impl<'a, Hash: Encode> codec::EncodeLike for DigestItemRef<'a, Hash> {}
 
 #[cfg(test)]
diff --git a/primitives/runtime/src/generic/mod.rs b/primitives/runtime/src/generic/mod.rs
index 2416bb70470be..5e9928ba1909a 100644
--- a/primitives/runtime/src/generic/mod.rs
+++ b/primitives/runtime/src/generic/mod.rs
@@ -33,7 +33,7 @@ pub use self::checked_extrinsic::CheckedExtrinsic;
 pub use self::header::Header;
 pub use self::block::{Block, SignedBlock, BlockId};
 pub use self::digest::{
-	Digest, DigestItem, DigestItemRef, OpaqueDigestItemId
+	Digest, DigestItem, DigestItemRef, OpaqueDigestItemId, ChangesTrieSignal,
 };
 
 use crate::codec::Encode;
diff --git a/primitives/runtime/src/lib.rs b/primitives/runtime/src/lib.rs
index c010ea0456d9e..6033f221a1f5f 100644
--- a/primitives/runtime/src/lib.rs
+++ b/primitives/runtime/src/lib.rs
@@ -53,6 +53,9 @@ pub mod testing;
 pub mod traits;
 pub mod transaction_validity;
 pub mod random_number_generator;
+mod runtime_string;
+
+pub use crate::runtime_string::*;
 
 /// Re-export these since they're only "kind of" generic.
 pub use generic::{DigestItem, Digest};
@@ -92,27 +95,6 @@ impl TypeId for ModuleId {
 	const TYPE_ID: [u8; 4] = *b"modl";
 }
 
-/// A String that is a `&'static str` on `no_std` and a `Cow<'static, str>` on `std`.
-#[cfg(feature = "std")]
-pub type RuntimeString = std::borrow::Cow<'static, str>;
-/// A String that is a `&'static str` on `no_std` and a `Cow<'static, str>` on `std`.
-#[cfg(not(feature = "std"))]
-pub type RuntimeString = &'static str;
-
-/// Create a const [`RuntimeString`].
-#[cfg(feature = "std")]
-#[macro_export]
-macro_rules! create_runtime_str {
-	( $y:expr ) => {{ std::borrow::Cow::Borrowed($y) }}
-}
-
-/// Create a const [`RuntimeString`].
-#[cfg(not(feature = "std"))]
-#[macro_export]
-macro_rules! create_runtime_str {
-	( $y:expr ) => {{ $y }}
-}
-
 #[cfg(feature = "std")]
 pub use serde::{Serialize, Deserialize, de::DeserializeOwned};
 use crate::traits::IdentifyAccount;
diff --git a/primitives/runtime/src/runtime_string.rs b/primitives/runtime/src/runtime_string.rs
new file mode 100644
index 0000000000000..e7ee927e087be
--- /dev/null
+++ b/primitives/runtime/src/runtime_string.rs
@@ -0,0 +1,117 @@
+// Copyright 2020 Parity Technologies (UK) Ltd.
+// This file is part of Substrate.
+
+// Substrate is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Substrate is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Substrate.  If not, see <http://www.gnu.org/licenses/>.
+
+use codec::{Encode, Decode};
+use sp_core::RuntimeDebug;
+use sp_std::vec::Vec;
+
+/// A string that wraps a `&'static str` in the runtime and `String`/`Vec<u8>` on decode.
+#[derive(Eq, RuntimeDebug, Clone)]
+pub enum RuntimeString {
+	/// The borrowed mode that wraps a `&'static str`.
+	Borrowed(&'static str),
+	/// The owned mode that wraps a `String`.
+	#[cfg(feature = "std")]
+	Owned(String),
+	/// The owned mode that wraps a `Vec<u8>`.
+	#[cfg(not(feature = "std"))]
+	Owned(Vec<u8>),
+}
+
+impl From<&'static str> for RuntimeString {
+	fn from(data: &'static str) -> Self {
+		Self::Borrowed(data)
+	}
+}
+
+#[cfg(feature = "std")]
+impl From<RuntimeString> for String {
+	fn from(string: RuntimeString) -> Self {
+		match string {
+			RuntimeString::Borrowed(data) => data.to_owned(),
+			RuntimeString::Owned(data) => data,
+		}
+	}
+}
+
+impl Default for RuntimeString {
+	fn default() -> Self {
+		Self::Borrowed(Default::default())
+	}
+}
+
+impl PartialEq for RuntimeString {
+	fn eq(&self, other: &Self) -> bool {
+		self.as_ref() == other.as_ref()
+	}
+}
+
+impl AsRef<[u8]> for RuntimeString {
+	fn as_ref(&self) -> &[u8] {
+		match self {
+			Self::Borrowed(val) => val.as_ref(),
+			Self::Owned(val) => val.as_ref(),
+		}
+	}
+}
+
+impl Encode for RuntimeString {
+	fn encode(&self) -> Vec<u8> {
+		match self {
+			Self::Borrowed(val) => val.encode(),
+			Self::Owned(val) => val.encode(),
+		}
+	}
+}
+
+impl Decode for RuntimeString {
+	fn decode<I: codec::Input>(value: &mut I) -> Result<Self, codec::Error> {
+		Decode::decode(value).map(Self::Owned)
+	}
+}
+
+#[cfg(feature = "std")]
+impl std::fmt::Display for RuntimeString {
+	fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+		match self {
+			Self::Borrowed(val) => write!(f, "{}", val),
+			Self::Owned(val) => write!(f, "{}", val),
+		}
+	}
+}
+
+#[cfg(feature = "std")]
+impl serde::Serialize for RuntimeString {
+	fn serialize<S: serde::Serializer>(&self, serializer: S) -> Result<S::Ok, S::Error> {
+		match self {
+			Self::Borrowed(val) => val.serialize(serializer),
+			Self::Owned(val) => val.serialize(serializer),
+		}
+	}
+}
+
+#[cfg(feature = "std")]
+impl<'de> serde::Deserialize<'de> for RuntimeString {
+	fn deserialize<D: serde::Deserializer<'de>>(de: D) -> Result<Self, D::Error> {
+		String::deserialize(de).map(Self::Owned)
+	}
+}
+
+/// Create a const [`RuntimeString`].
+#[macro_export]
+macro_rules! create_runtime_str {
+	( $y:expr ) => {{ $crate::RuntimeString::Borrowed($y) }}
+}
diff --git a/primitives/sandbox/Cargo.toml b/primitives/sandbox/Cargo.toml
index ff3b7662cd5a5..5d161a6deb9da 100755
--- a/primitives/sandbox/Cargo.toml
+++ b/primitives/sandbox/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "sp-sandbox"
-version = "2.0.0"
+version = "0.8.0"
 authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2018"
 
diff --git a/primitives/state-machine/Cargo.toml b/primitives/state-machine/Cargo.toml
index 1424845ea6cc9..d390471aca2d6 100644
--- a/primitives/state-machine/Cargo.toml
+++ b/primitives/state-machine/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "sp-state-machine"
-version = "2.0.0"
+version = "0.8.0"
 authors = ["Parity Technologies <admin@parity.io>"]
 description = "Substrate State Machine"
 edition = "2018"
@@ -9,7 +9,7 @@ edition = "2018"
 log = "0.4.8"
 parking_lot = "0.9.0"
 hash-db = "0.15.2"
-trie-db = "0.18.1"
+trie-db = "0.19.2"
 trie-root = "0.15.2"
 sp-trie = { version = "2.0.0", path = "../trie" }
 sp-core = { version = "2.0.0", path = "../core" }
@@ -17,7 +17,7 @@ sp-panic-handler = { version = "2.0.0", path = "../panic-handler" }
 codec = { package = "parity-scale-codec", version = "1.0.0" }
 num-traits = "0.2.8"
 rand = "0.7.2"
-sp-externalities = { version = "2.0.0", path = "../externalities" }
+sp-externalities = { version = "0.8.0", path = "../externalities" }
 
 [dev-dependencies]
 hex-literal = "0.2.1"
diff --git a/primitives/state-machine/src/backend.rs b/primitives/state-machine/src/backend.rs
index 75733d68b3ffa..4ef9b970ae21d 100644
--- a/primitives/state-machine/src/backend.rs
+++ b/primitives/state-machine/src/backend.rs
@@ -26,7 +26,7 @@ use sp_trie::{TrieMut, MemoryDB, trie_types::TrieDBMut};
 use crate::{
 	trie_backend::TrieBackend,
 	trie_backend_essence::TrieBackendStorage,
-	UsageInfo,
+	UsageInfo, StorageKey, StorageValue, StorageCollection,
 };
 
 /// A state backend is used to read state data and can have changes committed
@@ -44,7 +44,7 @@ pub trait Backend<H: Hasher>: std::fmt::Debug {
 	type TrieBackendStorage: TrieBackendStorage<H>;
 
 	/// Get keyed storage or None if there is nothing associated.
-	fn storage(&self, key: &[u8]) -> Result<Option<Vec<u8>>, Self::Error>;
+	fn storage(&self, key: &[u8]) -> Result<Option<StorageValue>, Self::Error>;
 
 	/// Get keyed storage value hash or None if there is nothing associated.
 	fn storage_hash(&self, key: &[u8]) -> Result<Option<H::Out>, Self::Error> {
@@ -57,7 +57,7 @@ pub trait Backend<H: Hasher>: std::fmt::Debug {
 		storage_key: &[u8],
 		child_info: ChildInfo,
 		key: &[u8],
-	) -> Result<Option<Vec<u8>>, Self::Error>;
+	) -> Result<Option<StorageValue>, Self::Error>;
 
 	/// Get child keyed storage value hash or None if there is nothing associated.
 	fn child_storage_hash(
@@ -85,7 +85,7 @@ pub trait Backend<H: Hasher>: std::fmt::Debug {
 	}
 
 	/// Return the next key in storage in lexicographic order or `None` if there is no value.
-	fn next_storage_key(&self, key: &[u8]) -> Result<Option<Vec<u8>>, Self::Error>;
+	fn next_storage_key(&self, key: &[u8]) -> Result<Option<StorageKey>, Self::Error>;
 
 	/// Return the next key in child storage in lexicographic order or `None` if there is no value.
 	fn next_child_storage_key(
@@ -93,7 +93,7 @@ pub trait Backend<H: Hasher>: std::fmt::Debug {
 		storage_key: &[u8],
 		child_info: ChildInfo,
 		key: &[u8]
-	) -> Result<Option<Vec<u8>>, Self::Error>;
+	) -> Result<Option<StorageKey>, Self::Error>;
 
 	/// Retrieve all entries keys of child storage and call `f` for each of those keys.
 	fn for_keys_in_child_storage<F: FnMut(&[u8])>(
@@ -129,7 +129,7 @@ pub trait Backend<H: Hasher>: std::fmt::Debug {
 	/// Does not include child storage updates.
 	fn storage_root<I>(&self, delta: I) -> (H::Out, Self::Transaction)
 	where
-		I: IntoIterator<Item=(Vec<u8>, Option<Vec<u8>>)>,
+		I: IntoIterator<Item=(StorageKey, Option<StorageValue>)>,
 		H::Out: Ord;
 
 	/// Calculate the child storage root, with given delta over what is already stored in
@@ -142,14 +142,14 @@ pub trait Backend<H: Hasher>: std::fmt::Debug {
 		delta: I,
 	) -> (H::Out, bool, Self::Transaction)
 	where
-		I: IntoIterator<Item=(Vec<u8>, Option<Vec<u8>>)>,
+		I: IntoIterator<Item=(StorageKey, Option<StorageValue>)>,
 		H::Out: Ord;
 
 	/// Get all key/value pairs into a Vec.
-	fn pairs(&self) -> Vec<(Vec<u8>, Vec<u8>)>;
+	fn pairs(&self) -> Vec<(StorageKey, StorageValue)>;
 
 	/// Get all keys with given prefix
-	fn keys(&self, prefix: &[u8]) -> Vec<Vec<u8>> {
+	fn keys(&self, prefix: &[u8]) -> Vec<StorageKey> {
 		let mut all = Vec::new();
 		self.for_keys_with_prefix(prefix, |k| all.push(k.to_vec()));
 		all
@@ -161,7 +161,7 @@ pub trait Backend<H: Hasher>: std::fmt::Debug {
 		storage_key: &[u8],
 		child_info: ChildInfo,
 		prefix: &[u8],
-	) -> Vec<Vec<u8>> {
+	) -> Vec<StorageKey> {
 		let mut all = Vec::new();
 		self.for_child_keys_with_prefix(storage_key, child_info, prefix, |k| all.push(k.to_vec()));
 		all
@@ -181,9 +181,9 @@ pub trait Backend<H: Hasher>: std::fmt::Debug {
 		child_deltas: I2)
 	-> (H::Out, Self::Transaction)
 	where
-		I1: IntoIterator<Item=(Vec<u8>, Option<Vec<u8>>)>,
-		I2i: IntoIterator<Item=(Vec<u8>, Option<Vec<u8>>)>,
-		I2: IntoIterator<Item=(Vec<u8>, I2i, OwnedChildInfo)>,
+		I1: IntoIterator<Item=(StorageKey, Option<StorageValue>)>,
+		I2i: IntoIterator<Item=(StorageKey, Option<StorageValue>)>,
+		I2: IntoIterator<Item=(StorageKey, I2i, OwnedChildInfo)>,
 		H::Out: Ord + Encode,
 	{
 		let mut txs: Self::Transaction = Default::default();
@@ -220,7 +220,7 @@ impl<'a, T: Backend<H>, H: Hasher> Backend<H> for &'a T {
 	type Transaction = T::Transaction;
 	type TrieBackendStorage = T::TrieBackendStorage;
 
-	fn storage(&self, key: &[u8]) -> Result<Option<Vec<u8>>, Self::Error> {
+	fn storage(&self, key: &[u8]) -> Result<Option<StorageKey>, Self::Error> {
 		(*self).storage(key)
 	}
 
@@ -229,7 +229,7 @@ impl<'a, T: Backend<H>, H: Hasher> Backend<H> for &'a T {
 		storage_key: &[u8],
 		child_info: ChildInfo,
 		key: &[u8],
-	) -> Result<Option<Vec<u8>>, Self::Error> {
+	) -> Result<Option<StorageKey>, Self::Error> {
 		(*self).child_storage(storage_key, child_info, key)
 	}
 
@@ -242,7 +242,7 @@ impl<'a, T: Backend<H>, H: Hasher> Backend<H> for &'a T {
 		(*self).for_keys_in_child_storage(storage_key, child_info, f)
 	}
 
-	fn next_storage_key(&self, key: &[u8]) -> Result<Option<Vec<u8>>, Self::Error> {
+	fn next_storage_key(&self, key: &[u8]) -> Result<Option<StorageKey>, Self::Error> {
 		(*self).next_storage_key(key)
 	}
 
@@ -251,7 +251,7 @@ impl<'a, T: Backend<H>, H: Hasher> Backend<H> for &'a T {
 		storage_key: &[u8],
 		child_info: ChildInfo,
 		key: &[u8],
-	) -> Result<Option<Vec<u8>>, Self::Error> {
+	) -> Result<Option<StorageKey>, Self::Error> {
 		(*self).next_child_storage_key(storage_key, child_info, key)
 	}
 
@@ -271,7 +271,7 @@ impl<'a, T: Backend<H>, H: Hasher> Backend<H> for &'a T {
 
 	fn storage_root<I>(&self, delta: I) -> (H::Out, Self::Transaction)
 	where
-		I: IntoIterator<Item=(Vec<u8>, Option<Vec<u8>>)>,
+		I: IntoIterator<Item=(StorageKey, Option<StorageValue>)>,
 		H::Out: Ord,
 	{
 		(*self).storage_root(delta)
@@ -284,13 +284,13 @@ impl<'a, T: Backend<H>, H: Hasher> Backend<H> for &'a T {
 		delta: I,
 	) -> (H::Out, bool, Self::Transaction)
 	where
-		I: IntoIterator<Item=(Vec<u8>, Option<Vec<u8>>)>,
+		I: IntoIterator<Item=(StorageKey, Option<StorageValue>)>,
 		H::Out: Ord,
 	{
 		(*self).child_storage_root(storage_key, child_info, delta)
 	}
 
-	fn pairs(&self) -> Vec<(Vec<u8>, Vec<u8>)> {
+	fn pairs(&self) -> Vec<(StorageKey, StorageValue)> {
 		(*self).pairs()
 	}
 
@@ -316,8 +316,8 @@ impl Consolidate for () {
 }
 
 impl Consolidate for Vec<(
-		Option<(Vec<u8>, OwnedChildInfo)>,
-		Vec<(Vec<u8>, Option<Vec<u8>>)>,
+		Option<(StorageKey, OwnedChildInfo)>,
+		StorageCollection,
 	)> {
 	fn consolidate(&mut self, mut other: Self) {
 		self.append(&mut other);
@@ -334,7 +334,7 @@ impl<H: Hasher, KF: sp_trie::KeyFunction<H>> Consolidate for sp_trie::GenericMem
 pub(crate) fn insert_into_memory_db<H, I>(mdb: &mut MemoryDB<H>, input: I) -> Option<H::Out>
 	where
 		H: Hasher,
-		I: IntoIterator<Item=(Vec<u8>, Vec<u8>)>,
+		I: IntoIterator<Item=(StorageKey, StorageValue)>,
 {
 	let mut root = <H as Hasher>::Out::default();
 	{
diff --git a/primitives/state-machine/src/basic.rs b/primitives/state-machine/src/basic.rs
index d06aedfc4b6ee..d905657737a8a 100644
--- a/primitives/state-machine/src/basic.rs
+++ b/primitives/state-machine/src/basic.rs
@@ -19,7 +19,7 @@
 use std::{
 	collections::BTreeMap, any::{TypeId, Any}, iter::FromIterator, ops::Bound
 };
-use crate::{Backend, InMemoryBackend};
+use crate::{Backend, InMemoryBackend, StorageKey, StorageValue};
 use hash_db::Hasher;
 use sp_trie::{TrieConfiguration, default_child_trie_root};
 use sp_trie::trie_types::Layout;
@@ -46,7 +46,7 @@ impl BasicExternalities {
 	}
 
 	/// Insert key/value
-	pub fn insert(&mut self, k: Vec<u8>, v: Vec<u8>) -> Option<Vec<u8>> {
+	pub fn insert(&mut self, k: StorageKey, v: StorageValue) -> Option<StorageValue> {
 		self.inner.top.insert(k, v)
 	}
 
@@ -89,8 +89,8 @@ impl PartialEq for BasicExternalities {
 	}
 }
 
-impl FromIterator<(Vec<u8>, Vec<u8>)> for BasicExternalities {
-	fn from_iter<I: IntoIterator<Item=(Vec<u8>, Vec<u8>)>>(iter: I) -> Self {
+impl FromIterator<(StorageKey, StorageValue)> for BasicExternalities {
+	fn from_iter<I: IntoIterator<Item=(StorageKey, StorageValue)>>(iter: I) -> Self {
 		let mut t = Self::default();
 		t.inner.top.extend(iter);
 		t
@@ -101,8 +101,8 @@ impl Default for BasicExternalities {
 	fn default() -> Self { Self::new(Default::default()) }
 }
 
-impl From<BTreeMap<Vec<u8>, Vec<u8>>> for BasicExternalities {
-	fn from(hashmap: BTreeMap<Vec<u8>, Vec<u8>>) -> Self {
+impl From<BTreeMap<StorageKey, StorageValue>> for BasicExternalities {
+	fn from(hashmap: BTreeMap<StorageKey, StorageValue>) -> Self {
 		BasicExternalities { inner: Storage {
 			top: hashmap,
 			children: Default::default(),
@@ -111,7 +111,7 @@ impl From<BTreeMap<Vec<u8>, Vec<u8>>> for BasicExternalities {
 }
 
 impl Externalities for BasicExternalities {
-	fn storage(&self, key: &[u8]) -> Option<Vec<u8>> {
+	fn storage(&self, key: &[u8]) -> Option<StorageValue> {
 		self.inner.top.get(key).cloned()
 	}
 
@@ -119,7 +119,7 @@ impl Externalities for BasicExternalities {
 		self.storage(key).map(|v| Blake2Hasher::hash(&v).encode())
 	}
 
-	fn original_storage(&self, key: &[u8]) -> Option<Vec<u8>> {
+	fn original_storage(&self, key: &[u8]) -> Option<StorageValue> {
 		self.storage(key)
 	}
 
@@ -132,7 +132,7 @@ impl Externalities for BasicExternalities {
 		storage_key: ChildStorageKey,
 		_child_info: ChildInfo,
 		key: &[u8],
-	) -> Option<Vec<u8>> {
+	) -> Option<StorageValue> {
 		self.inner.children.get(storage_key.as_ref()).and_then(|child| child.data.get(key)).cloned()
 	}
 
@@ -159,11 +159,11 @@ impl Externalities for BasicExternalities {
 		storage_key: ChildStorageKey,
 		child_info: ChildInfo,
 		key: &[u8],
-	) -> Option<Vec<u8>> {
+	) -> Option<StorageValue> {
 		Externalities::child_storage(self, storage_key, child_info, key)
 	}
 
-	fn next_storage_key(&self, key: &[u8]) -> Option<Vec<u8>> {
+	fn next_storage_key(&self, key: &[u8]) -> Option<StorageKey> {
 		let range = (Bound::Excluded(key), Bound::Unbounded);
 		self.inner.top.range::<[u8], _>(range).next().map(|(k, _)| k).cloned()
 	}
@@ -173,13 +173,13 @@ impl Externalities for BasicExternalities {
 		storage_key: ChildStorageKey,
 		_child_info: ChildInfo,
 		key: &[u8],
-	) -> Option<Vec<u8>> {
+	) -> Option<StorageKey> {
 		let range = (Bound::Excluded(key), Bound::Unbounded);
 		self.inner.children.get(storage_key.as_ref())
 			.and_then(|child| child.data.range::<[u8], _>(range).next().map(|(k, _)| k).cloned())
 	}
 
-	fn place_storage(&mut self, key: Vec<u8>, maybe_value: Option<Vec<u8>>) {
+	fn place_storage(&mut self, key: StorageKey, maybe_value: Option<StorageValue>) {
 		if is_child_storage_key(&key) {
 			warn!(target: "trie", "Refuse to set child storage key via main storage");
 			return;
@@ -195,8 +195,8 @@ impl Externalities for BasicExternalities {
 		&mut self,
 		storage_key: ChildStorageKey,
 		child_info: ChildInfo,
-		key: Vec<u8>,
-		value: Option<Vec<u8>>,
+		key: StorageKey,
+		value: Option<StorageValue>,
 	) {
 		let child_map = self.inner.children.entry(storage_key.into_owned())
 			.or_insert_with(|| StorageChild {
diff --git a/primitives/state-machine/src/changes_trie/build.rs b/primitives/state-machine/src/changes_trie/build.rs
index ded8e4f6d19ed..c731d4104b260 100644
--- a/primitives/state-machine/src/changes_trie/build.rs
+++ b/primitives/state-machine/src/changes_trie/build.rs
@@ -21,13 +21,17 @@ use std::collections::btree_map::Entry;
 use codec::{Decode, Encode};
 use hash_db::Hasher;
 use num_traits::One;
-use crate::backend::Backend;
-use crate::overlayed_changes::OverlayedChanges;
-use crate::trie_backend_essence::TrieBackendEssence;
-use crate::changes_trie::build_iterator::digest_build_iterator;
-use crate::changes_trie::input::{InputKey, InputPair, DigestIndex, ExtrinsicIndex};
-use crate::changes_trie::{AnchorBlockId, ConfigurationRange, Storage, BlockNumber};
-use crate::changes_trie::input::ChildIndex;
+use crate::{
+	StorageKey,
+	backend::Backend,
+	overlayed_changes::OverlayedChanges,
+	trie_backend_essence::TrieBackendEssence,
+	changes_trie::{
+		AnchorBlockId, ConfigurationRange, Storage, BlockNumber,
+		build_iterator::digest_build_iterator,
+		input::{InputKey, InputPair, DigestIndex, ExtrinsicIndex, ChildIndex},
+	},
+};
 
 /// Prepare input pairs for building a changes trie of given block.
 ///
@@ -101,7 +105,7 @@ fn prepare_extrinsics_input<'a, B, H, Number>(
 		Number: BlockNumber,
 {
 
-	let mut children_keys = BTreeSet::<Vec<u8>>::new();
+	let mut children_keys = BTreeSet::<StorageKey>::new();
 	let mut children_result = BTreeMap::new();
 	for (storage_key, _) in changes.prospective.children.iter()
 		.chain(changes.committed.children.iter()) {
@@ -126,7 +130,7 @@ fn prepare_extrinsics_input_inner<'a, B, H, Number>(
 	backend: &'a B,
 	block: &Number,
 	changes: &'a OverlayedChanges,
-	storage_key: Option<Vec<u8>>,
+	storage_key: Option<StorageKey>,
 ) -> Result<impl Iterator<Item=InputPair<Number>> + 'a, String>
 	where
 		B: Backend<H>,
@@ -231,7 +235,7 @@ fn prepare_digest_input<'a, H, Number>(
 			let trie_root = storage.root(parent, digest_build_block.clone())?;
 			let trie_root = trie_root.ok_or_else(|| format!("No changes trie root for block {}", digest_build_block.clone()))?;
 
-			let insert_to_map = |map: &mut BTreeMap<_,_>, key: Vec<u8>| {
+			let insert_to_map = |map: &mut BTreeMap<_,_>, key: StorageKey| {
 				match map.entry(key.clone()) {
 					Entry::Vacant(entry) => {
 						entry.insert((DigestIndex {
@@ -277,7 +281,7 @@ fn prepare_digest_input<'a, H, Number>(
 				return Ok((map, child_map));
 			}
 
-			let mut children_roots = BTreeMap::<Vec<u8>, _>::new();
+			let mut children_roots = BTreeMap::<StorageKey, _>::new();
 			{
 				let trie_storage = TrieBackendEssence::<_, H>::new(
 					crate::changes_trie::TrieBackendStorageAdapter(storage),
@@ -356,7 +360,6 @@ mod test {
 		OverlayedChanges,
 		Configuration,
 	) {
-		let config = Configuration { digest_interval: 4, digest_levels: 2 };
 		let backend: InMemoryBackend<_> = vec![
 			(vec![100], vec![255]),
 			(vec![101], vec![255]),
@@ -465,8 +468,9 @@ mod test {
 					].into_iter().collect(), CHILD_INFO_1.to_owned())),
 				].into_iter().collect(),
 			},
-			changes_trie_config: Some(config.clone()),
+			collect_extrinsics: true,
 		};
+		let config = Configuration { digest_interval: 4, digest_levels: 2 };
 
 		(backend, storage, changes, config)
 	}
@@ -553,7 +557,6 @@ mod test {
 						InputPair::ExtrinsicIndex(ExtrinsicIndex { block: zero + 4, key: vec![100] }, vec![0, 2]),
 					]),
 			]);
-
 		}
 
 		test_with_zero(0);
@@ -597,7 +600,6 @@ mod test {
 						InputPair::ExtrinsicIndex(ExtrinsicIndex { block: zero + 16, key: vec![100] }, vec![0, 2]),
 					]),
 			]);
-
 		}
 
 		test_with_zero(0);
@@ -706,8 +708,7 @@ mod test {
 
 	#[test]
 	fn cache_is_used_when_changes_trie_is_built() {
-		let (backend, mut storage, changes, _) = prepare_for_build(0);
-		let config = changes.changes_trie_config.as_ref().unwrap();
+		let (backend, mut storage, changes, config) = prepare_for_build(0);
 		let parent = AnchorBlockId { hash: Default::default(), number: 15 };
 
 		// override some actual values from storage with values from the cache
@@ -770,6 +771,5 @@ mod test {
 				InputPair::DigestIndex(DigestIndex { block: 16u64, key: vec![106] }, vec![4]),
 			],
 		);
-
 	}
 }
diff --git a/primitives/state-machine/src/changes_trie/build_cache.rs b/primitives/state-machine/src/changes_trie/build_cache.rs
index 76e3652e16681..9d0dbb4c1f310 100644
--- a/primitives/state-machine/src/changes_trie/build_cache.rs
+++ b/primitives/state-machine/src/changes_trie/build_cache.rs
@@ -18,6 +18,8 @@
 
 use std::collections::{HashMap, HashSet};
 
+use crate::StorageKey;
+
 /// Changes trie build cache.
 ///
 /// Helps to avoid read of changes tries from the database when digest trie
@@ -36,7 +38,7 @@ pub struct BuildCache<H, N> {
 	/// The `Option<Vec<u8>>` in inner `HashMap` stands for the child storage key.
 	/// If it is `None`, then the `HashSet` contains keys changed in top-level storage.
 	/// If it is `Some`, then the `HashSet` contains keys changed in child storage, identified by the key.
-	changed_keys: HashMap<H, HashMap<Option<Vec<u8>>, HashSet<Vec<u8>>>>,
+	changed_keys: HashMap<H, HashMap<Option<StorageKey>, HashSet<StorageKey>>>,
 }
 
 /// The action to perform when block-with-changes-trie is imported.
@@ -54,7 +56,7 @@ pub struct CachedBuildData<H, N> {
 	block: N,
 	trie_root: H,
 	digest_input_blocks: Vec<N>,
-	changed_keys: HashMap<Option<Vec<u8>>, HashSet<Vec<u8>>>,
+	changed_keys: HashMap<Option<StorageKey>, HashSet<StorageKey>>,
 }
 
 /// The action to perform when block-with-changes-trie is imported.
@@ -70,7 +72,7 @@ pub(crate) enum IncompleteCacheAction<N> {
 #[derive(Debug, PartialEq)]
 pub(crate) struct IncompleteCachedBuildData<N> {
 	digest_input_blocks: Vec<N>,
-	changed_keys: HashMap<Option<Vec<u8>>, HashSet<Vec<u8>>>,
+	changed_keys: HashMap<Option<StorageKey>, HashSet<StorageKey>>,
 }
 
 impl<H, N> BuildCache<H, N>
@@ -87,7 +89,7 @@ impl<H, N> BuildCache<H, N>
 	}
 
 	/// Get cached changed keys for changes trie with given root.
-	pub fn get(&self, root: &H) -> Option<&HashMap<Option<Vec<u8>>, HashSet<Vec<u8>>>> {
+	pub fn get(&self, root: &H) -> Option<&HashMap<Option<StorageKey>, HashSet<StorageKey>>> {
 		self.changed_keys.get(&root)
 	}
 
@@ -96,7 +98,7 @@ impl<H, N> BuildCache<H, N>
 	pub fn with_changed_keys(
 		&self,
 		root: &H,
-		functor: &mut dyn FnMut(&HashMap<Option<Vec<u8>>, HashSet<Vec<u8>>>),
+		functor: &mut dyn FnMut(&HashMap<Option<StorageKey>, HashSet<StorageKey>>),
 	) -> bool {
 		match self.changed_keys.get(&root) {
 			Some(changed_keys) => {
@@ -162,8 +164,8 @@ impl<N> IncompleteCacheAction<N> {
 	/// Insert changed keys of given storage into cached data.
 	pub(crate) fn insert(
 		self,
-		storage_key: Option<Vec<u8>>,
-		changed_keys: HashSet<Vec<u8>>,
+		storage_key: Option<StorageKey>,
+		changed_keys: HashSet<StorageKey>,
 	) -> Self {
 		match self {
 			IncompleteCacheAction::CacheBuildData(build_data) =>
@@ -198,8 +200,8 @@ impl<N> IncompleteCachedBuildData<N> {
 
 	fn insert(
 		mut self,
-		storage_key: Option<Vec<u8>>,
-		changed_keys: HashSet<Vec<u8>>,
+		storage_key: Option<StorageKey>,
+		changed_keys: HashSet<StorageKey>,
 	) -> Self {
 		self.changed_keys.insert(storage_key, changed_keys);
 		self
@@ -259,4 +261,4 @@ mod tests {
 
 		assert_eq!(cache.changed_keys.len(), 0);
 	}
-}
\ No newline at end of file
+}
diff --git a/primitives/state-machine/src/changes_trie/input.rs b/primitives/state-machine/src/changes_trie/input.rs
index 9b3341ca5842b..4a1420f8486f9 100644
--- a/primitives/state-machine/src/changes_trie/input.rs
+++ b/primitives/state-machine/src/changes_trie/input.rs
@@ -17,7 +17,10 @@
 //! Different types of changes trie input pairs.
 
 use codec::{Decode, Encode, Input, Output, Error};
-use crate::changes_trie::BlockNumber;
+use crate::{
+	StorageKey, StorageValue,
+	changes_trie::BlockNumber
+};
 
 /// Key of { changed key => set of extrinsic indices } mapping.
 #[derive(Clone, Debug, PartialEq, Eq)]
@@ -25,7 +28,7 @@ pub struct ExtrinsicIndex<Number: BlockNumber> {
 	/// Block at which this key has been inserted in the trie.
 	pub block: Number,
 	/// Storage key this node is responsible for.
-	pub key: Vec<u8>,
+	pub key: StorageKey,
 }
 
 /// Value of { changed key => set of extrinsic indices } mapping.
@@ -37,7 +40,7 @@ pub struct DigestIndex<Number: BlockNumber> {
 	/// Block at which this key has been inserted in the trie.
 	pub block: Number,
 	/// Storage key this node is responsible for.
-	pub key: Vec<u8>,
+	pub key: StorageKey,
 }
 
 /// Key of { childtrie key => Childchange trie } mapping.
@@ -46,7 +49,7 @@ pub struct ChildIndex<Number: BlockNumber> {
 	/// Block at which this key has been inserted in the trie.
 	pub block: Number,
 	/// Storage key this node is responsible for.
-	pub storage_key: Vec<u8>,
+	pub storage_key: StorageKey,
 }
 
 /// Value of { changed key => block/digest block numbers } mapping.
@@ -89,8 +92,8 @@ impl<Number: BlockNumber> InputPair<Number> {
 	}
 }
 
-impl<Number: BlockNumber> Into<(Vec<u8>, Vec<u8>)> for InputPair<Number> {
-	fn into(self) -> (Vec<u8>, Vec<u8>) {
+impl<Number: BlockNumber> Into<(StorageKey, StorageValue)> for InputPair<Number> {
+	fn into(self) -> (StorageKey, StorageValue) {
 		match self {
 			InputPair::ExtrinsicIndex(key, value) => (key.encode(), value.encode()),
 			InputPair::DigestIndex(key, value) => (key.encode(), value.encode()),
diff --git a/primitives/state-machine/src/changes_trie/mod.rs b/primitives/state-machine/src/changes_trie/mod.rs
index cb19d157dd80a..12074b7261aa5 100644
--- a/primitives/state-machine/src/changes_trie/mod.rs
+++ b/primitives/state-machine/src/changes_trie/mod.rs
@@ -63,20 +63,25 @@ pub use self::changes_iterator::{
 	key_changes, key_changes_proof,
 	key_changes_proof_check, key_changes_proof_check_with_db,
 };
-pub use self::prune::{prune, oldest_non_pruned_trie};
+pub use self::prune::prune;
 
 use std::collections::{HashMap, HashSet};
 use std::convert::TryInto;
 use hash_db::{Hasher, Prefix};
-use crate::backend::Backend;
 use num_traits::{One, Zero};
 use codec::{Decode, Encode};
 use sp_core;
-use crate::changes_trie::build::prepare_input;
-use crate::changes_trie::build_cache::{IncompleteCachedBuildData, IncompleteCacheAction};
-use crate::overlayed_changes::OverlayedChanges;
 use sp_trie::{MemoryDB, DBValue, TrieMut};
 use sp_trie::trie_types::TrieDBMut;
+use crate::{
+	StorageKey,
+	backend::Backend,
+	overlayed_changes::OverlayedChanges,
+	changes_trie::{
+		build::prepare_input,
+		build_cache::{IncompleteCachedBuildData, IncompleteCacheAction},
+	},
+};
 
 /// Changes that are made outside of extrinsics are marked with this index;
 pub const NO_EXTRINSIC_INDEX: u32 = 0xffffffff;
@@ -121,6 +126,18 @@ pub struct AnchorBlockId<Hash: std::fmt::Debug, Number: BlockNumber> {
 	pub number: Number,
 }
 
+/// Changes tries state at some block.
+pub struct State<'a, H, Number> {
+	/// Configuration that is active at given block.
+	pub config: Configuration,
+	/// Configuration activation block number. Zero if it is the first coonfiguration on the chain,
+	/// or number of the block that have emit NewConfiguration signal (thus activating configuration
+	/// starting from the **next** block).
+	pub zero: Number,
+	/// Underlying changes tries storage reference.
+	pub storage: &'a dyn Storage<H, Number>,
+}
+
 /// Changes trie storage. Provides access to trie roots and trie nodes.
 pub trait RootsStorage<H: Hasher, Number: BlockNumber>: Send + Sync {
 	/// Resolve hash of the block into anchor.
@@ -139,7 +156,7 @@ pub trait Storage<H: Hasher, Number: BlockNumber>: RootsStorage<H, Number> {
 	fn with_cached_changed_keys(
 		&self,
 		root: &H::Out,
-		functor: &mut dyn FnMut(&HashMap<Option<Vec<u8>>, HashSet<Vec<u8>>>),
+		functor: &mut dyn FnMut(&HashMap<Option<StorageKey>, HashSet<StorageKey>>),
 	) -> bool;
 	/// Get a trie node.
 	fn get(&self, key: &H::Out, prefix: Prefix) -> Result<Option<DBValue>, String>;
@@ -170,14 +187,43 @@ pub struct ConfigurationRange<'a, N> {
 	pub end: Option<N>,
 }
 
+impl<'a, H, Number> State<'a, H, Number> {
+	/// Create state with given config and storage.
+	pub fn new(
+		config: Configuration,
+		zero: Number,
+		storage: &'a dyn Storage<H, Number>,
+	) -> Self {
+		Self {
+			config,
+			zero,
+			storage,
+		}
+	}
+}
+
+impl<'a, H, Number: Clone> Clone for State<'a, H, Number> {
+	fn clone(&self) -> Self {
+		State {
+			config: self.config.clone(),
+			zero: self.zero.clone(),
+			storage: self.storage,
+		}
+	}
+}
+
+/// Create state where changes tries are disabled.
+pub fn disabled_state<'a, H, Number>() -> Option<State<'a, H, Number>> {
+	None
+}
+
 /// Compute the changes trie root and transaction for given block.
 /// Returns Err(()) if unknown `parent_hash` has been passed.
 /// Returns Ok(None) if there's no data to perform computation.
-/// Panics if background storage returns an error (and `panic_on_storage_error` is `true`) OR
-/// if insert to MemoryDB fails.
-pub fn build_changes_trie<'a, B: Backend<H>, S: Storage<H, Number>, H: Hasher, Number: BlockNumber>(
+/// Panics if background storage returns an error OR if insert to MemoryDB fails.
+pub fn build_changes_trie<'a, B: Backend<H>, H: Hasher, Number: BlockNumber>(
 	backend: &B,
-	storage: Option<&'a S>,
+	state: Option<&'a State<'a, H, Number>>,
 	changes: &OverlayedChanges,
 	parent_hash: H::Out,
 	panic_on_storage_error: bool,
@@ -185,11 +231,6 @@ pub fn build_changes_trie<'a, B: Backend<H>, S: Storage<H, Number>, H: Hasher, N
 	where
 		H::Out: Ord + 'static + Encode,
 {
-	let (storage, config) = match (storage, changes.changes_trie_config.as_ref()) {
-		(Some(storage), Some(config)) => (storage, config),
-		_ => return Ok(None),
-	};
-
 	/// Panics when `res.is_err() && panic`, otherwise it returns `Err(())` on an error.
 	fn maybe_panic<R, E: std::fmt::Debug>(
 		res: std::result::Result<R, E>,
@@ -203,23 +244,35 @@ pub fn build_changes_trie<'a, B: Backend<H>, S: Storage<H, Number>, H: Hasher, N
 			})
 	}
 
-	// FIXME: remove this in https://github.com/paritytech/substrate/pull/3201
-	let config = ConfigurationRange {
-		config,
-		zero: Zero::zero(),
-		end: None,
+	// when storage isn't provided, changes tries aren't created
+	let state = match state {
+		Some(state) => state,
+		None => return Ok(None),
 	};
 
 	// build_anchor error should not be considered fatal
-	let parent = storage.build_anchor(parent_hash).map_err(|_| ())?;
+	let parent = state.storage.build_anchor(parent_hash).map_err(|_| ())?;
 	let block = parent.number.clone() + One::one();
 
+	// prepare configuration range - we already know zero block. Current block may be the end block if configuration
+	// has been changed in this block
+	let is_config_changed = match changes.storage(sp_core::storage::well_known_keys::CHANGES_TRIE_CONFIG) {
+		Some(Some(new_config)) => new_config != &state.config.encode()[..],
+		Some(None) => true,
+		None => false,
+	};
+	let config_range = ConfigurationRange {
+		config: &state.config,
+		zero: state.zero.clone(),
+		end: if is_config_changed { Some(block.clone()) } else { None },
+	};
+
 	// storage errors are considered fatal (similar to situations when runtime fetches values from storage)
 	let (input_pairs, child_input_pairs, digest_input_blocks) = maybe_panic(
 		prepare_input::<B, H, Number>(
 			backend,
-			storage,
-			config.clone(),
+			state.storage,
+			config_range.clone(),
 			changes,
 			&parent,
 		),
@@ -227,7 +280,7 @@ pub fn build_changes_trie<'a, B: Backend<H>, S: Storage<H, Number>, H: Hasher, N
 	)?;
 
 	// prepare cached data
-	let mut cache_action = prepare_cached_build_data(config, block.clone());
+	let mut cache_action = prepare_cached_build_data(config_range, block.clone());
 	let needs_changed_keys = cache_action.collects_changed_keys();
 	cache_action = cache_action.set_digest_input_blocks(digest_input_blocks);
 
diff --git a/primitives/state-machine/src/changes_trie/prune.rs b/primitives/state-machine/src/changes_trie/prune.rs
index e16daea15821e..f6be3223ae9f8 100644
--- a/primitives/state-machine/src/changes_trie/prune.rs
+++ b/primitives/state-machine/src/changes_trie/prune.rs
@@ -19,52 +19,26 @@
 use hash_db::Hasher;
 use sp_trie::Recorder;
 use log::warn;
-use num_traits::{One, Zero};
+use num_traits::One;
 use crate::proving_backend::ProvingBackendRecorder;
 use crate::trie_backend_essence::TrieBackendEssence;
-use crate::changes_trie::{AnchorBlockId, Configuration, Storage, BlockNumber};
+use crate::changes_trie::{AnchorBlockId, Storage, BlockNumber};
 use crate::changes_trie::storage::TrieBackendAdapter;
 use crate::changes_trie::input::{ChildIndex, InputKey};
 use codec::{Decode, Codec};
 
-/// Get number of oldest block for which changes trie is not pruned
-/// given changes trie configuration, pruning parameter and number of
-/// best finalized block.
-pub fn oldest_non_pruned_trie<Number: BlockNumber>(
-	config: &Configuration,
-	min_blocks_to_keep: Number,
-	best_finalized_block: Number,
-) -> Number {
-	let max_digest_interval = config.max_digest_interval();
-	let best_finalized_block_rem = best_finalized_block.clone() % max_digest_interval.into();
-	let max_digest_block = best_finalized_block - best_finalized_block_rem;
-	match pruning_range(config, min_blocks_to_keep, max_digest_block) {
-		Some((_, last_pruned_block)) => last_pruned_block + One::one(),
-		None => One::one(),
-	}
-}
-
 /// Prune obsolete changes tries. Pruning happens at the same block, where highest
 /// level digest is created. Pruning guarantees to save changes tries for last
 /// `min_blocks_to_keep` blocks. We only prune changes tries at `max_digest_interval`
 /// ranges.
-/// Returns MemoryDB that contains all deleted changes tries nodes.
-pub fn prune<S: Storage<H, Number>, H: Hasher, Number: BlockNumber, F: FnMut(H::Out)>(
-	config: &Configuration,
-	storage: &S,
-	min_blocks_to_keep: Number,
+pub fn prune<H: Hasher, Number: BlockNumber, F: FnMut(H::Out)>(
+	storage: &dyn Storage<H, Number>,
+	first: Number,
+	last: Number,
 	current_block: &AnchorBlockId<H::Out, Number>,
 	mut remove_trie_node: F,
 ) where H::Out: Codec {
-
-	// select range for pruning
-	let (first, last) = match pruning_range(config, min_blocks_to_keep, current_block.number.clone()) {
-		Some((first, last)) => (first, last),
-		None => return,
-	};
-
 	// delete changes trie for every block in range
-	// FIXME: limit `max_digest_interval` so that this cycle won't involve huge ranges
 	let mut block = first;
 	loop {
 		if block >= last.clone() + One::one() {
@@ -112,8 +86,8 @@ pub fn prune<S: Storage<H, Number>, H: Hasher, Number: BlockNumber, F: FnMut(H::
 }
 
 // Prune a trie.
-fn prune_trie<S: Storage<H, Number>, H: Hasher, Number: BlockNumber, F: FnMut(H::Out)>(
-	storage: &S,
+fn prune_trie<H: Hasher, Number: BlockNumber, F: FnMut(H::Out)>(
+	storage: &dyn Storage<H, Number>,
 	root: H::Out,
 	remove_trie_node: &mut F,
 ) where H::Out: Codec {
@@ -136,100 +110,26 @@ fn prune_trie<S: Storage<H, Number>, H: Hasher, Number: BlockNumber, F: FnMut(H:
 	}
 }
 
-/// Select blocks range (inclusive from both ends) for pruning changes tries in.
-fn pruning_range<Number: BlockNumber>(
-	config: &Configuration,
-	min_blocks_to_keep: Number,
-	block: Number,
-) -> Option<(Number, Number)> {
-	// compute number of changes tries we actually want to keep
-	let (prune_interval, blocks_to_keep) = if config.is_digest_build_enabled() {
-		// we only CAN prune at block where max-level-digest is created
-		let max_digest_interval = match config.digest_level_at_block(Zero::zero(), block.clone()) {
-			Some((digest_level, digest_interval, _)) if digest_level == config.digest_levels =>
-				digest_interval,
-			_ => return None,
-		};
-
-		// compute maximal number of high-level digests to keep
-		let max_digest_intervals_to_keep = max_digest_intervals_to_keep(min_blocks_to_keep, max_digest_interval);
-
-		// number of blocks BEFORE current block where changes tries are not pruned
-		(
-			max_digest_interval,
-			max_digest_intervals_to_keep.checked_mul(&max_digest_interval.into())
-		)
-	} else {
-		(
-			1,
-			Some(min_blocks_to_keep)
-		)
-	};
-
-	// last block for which changes trie is pruned
-	let last_block_to_prune = blocks_to_keep.and_then(|b| block.checked_sub(&b));
-	let first_block_to_prune = last_block_to_prune
-		.clone()
-		.and_then(|b| b.checked_sub(&prune_interval.into()));
-
-	last_block_to_prune
-		.and_then(|last| first_block_to_prune.map(|first| (first + One::one(), last)))
-}
-
-/// Select pruning delay for the changes tries. To make sure we could build a changes
-/// trie at block B, we need an access to previous:
-/// max_digest_interval = config.digest_interval ^ config.digest_levels
-/// blocks. So we can only prune blocks that are earlier than B - max_digest_interval.
-/// The pruning_delay stands for number of max_digest_interval-s that we want to keep:
-/// 0 or 1: means that only last changes trie is guaranteed to exists;
-/// 2: the last changes trie + previous changes trie
-/// ...
-fn max_digest_intervals_to_keep<Number: BlockNumber>(
-	min_blocks_to_keep: Number,
-	max_digest_interval: u32,
-) -> Number {
-	// config.digest_level_at_block ensures that it is not zero
-	debug_assert!(max_digest_interval != 0);
-
-	let max_digest_intervals_to_keep = min_blocks_to_keep / max_digest_interval.into();
-	if max_digest_intervals_to_keep.is_zero() {
-		One::one()
-	} else {
-		max_digest_intervals_to_keep
-	}
-}
-
 #[cfg(test)]
 mod tests {
 	use std::collections::HashSet;
 	use sp_trie::MemoryDB;
-	use sp_core::Blake2Hasher;
+	use sp_core::{H256, Blake2Hasher};
 	use crate::backend::insert_into_memory_db;
 	use crate::changes_trie::storage::InMemoryStorage;
 	use codec::Encode;
 	use super::*;
 
-	fn config(interval: u32, levels: u32) -> Configuration {
-		Configuration {
-			digest_interval: interval,
-			digest_levels: levels,
-		}
-	}
-
-	fn prune_by_collect<S: Storage<H, u64>, H: Hasher>(
-		config: &Configuration,
-		storage: &S,
-		min_blocks_to_keep: u64,
+	fn prune_by_collect(
+		storage: &dyn Storage<Blake2Hasher, u64>,
+		first: u64,
+		last: u64,
 		current_block: u64,
-	) -> HashSet<H::Out> where H::Out: Codec {
+	) -> HashSet<H256> {
 		let mut pruned_trie_nodes = HashSet::new();
-		prune(
-			config,
-			storage,
-			min_blocks_to_keep,
-			&AnchorBlockId { hash: Default::default(), number: current_block },
-			|node| { pruned_trie_nodes.insert(node); },
-		);
+		let anchor = AnchorBlockId { hash: Default::default(), number: current_block };
+		prune(storage, first, last, &anchor,
+			|node| { pruned_trie_nodes.insert(node); });
 		pruned_trie_nodes
 	}
 
@@ -243,7 +143,9 @@ mod tests {
 				&mut mdb1, vec![(vec![10], vec![20])]).unwrap();
 			let mut mdb2 = MemoryDB::<Blake2Hasher>::default();
 			let root2 = insert_into_memory_db::<Blake2Hasher, _>(
-				&mut mdb2, vec![(vec![11], vec![21]), (vec![12], vec![22])]).unwrap();
+				&mut mdb2,
+				vec![(vec![11], vec![21]), (vec![12], vec![22])],
+			).unwrap();
 			let mut mdb3 = MemoryDB::<Blake2Hasher>::default();
 			let ch_root3 = insert_into_memory_db::<Blake2Hasher, _>(
 				&mut mdb3, vec![(vec![110], vec![120])]).unwrap();
@@ -254,7 +156,9 @@ mod tests {
 			]).unwrap();
 			let mut mdb4 = MemoryDB::<Blake2Hasher>::default();
 			let root4 = insert_into_memory_db::<Blake2Hasher, _>(
-				&mut mdb4, vec![(vec![15], vec![25])]).unwrap();
+				&mut mdb4,
+				vec![(vec![15], vec![25])],
+			).unwrap();
 			let storage = InMemoryStorage::new();
 			storage.insert(65, root1, mdb1);
 			storage.insert(66, root2, mdb2);
@@ -264,109 +168,20 @@ mod tests {
 			storage
 		}
 
-		// l1-digest is created every 2 blocks
-		// l2-digest is created every 4 blocks
-		// we do not want to keep any additional changes tries
-		// => only one l2-digest is saved AND it is pruned once next is created
-		let config = Configuration { digest_interval: 2, digest_levels: 2 };
 		let storage = prepare_storage();
-		assert!(prune_by_collect(&config, &storage, 0, 69).is_empty());
-		assert!(prune_by_collect(&config, &storage, 0, 70).is_empty());
-		assert!(prune_by_collect(&config, &storage, 0, 71).is_empty());
-		let non_empty = prune_by_collect(&config, &storage, 0, 72);
-		assert!(!non_empty.is_empty());
-		storage.remove_from_storage(&non_empty);
-		assert!(storage.into_mdb().drain().is_empty());
+		assert!(prune_by_collect(&storage, 20, 30, 90).is_empty());
+		assert!(!storage.into_mdb().drain().is_empty());
 
-		// l1-digest is created every 2 blocks
-		// l2-digest is created every 4 blocks
-		// we want keep 1 additional changes tries
-		let config = Configuration { digest_interval: 2, digest_levels: 2 };
 		let storage = prepare_storage();
-		assert!(prune_by_collect(&config, &storage, 8, 69).is_empty());
-		assert!(prune_by_collect(&config, &storage, 8, 70).is_empty());
-		assert!(prune_by_collect(&config, &storage, 8, 71).is_empty());
-		assert!(prune_by_collect(&config, &storage, 8, 72).is_empty());
-		assert!(prune_by_collect(&config, &storage, 8, 73).is_empty());
-		assert!(prune_by_collect(&config, &storage, 8, 74).is_empty());
-		assert!(prune_by_collect(&config, &storage, 8, 75).is_empty());
-		let non_empty = prune_by_collect(&config, &storage, 8, 76);
-		assert!(!non_empty.is_empty());
-		storage.remove_from_storage(&non_empty);
-		assert!(storage.into_mdb().drain().is_empty());
+		let prune60_65 = prune_by_collect(&storage, 60, 65, 90);
+		assert!(!prune60_65.is_empty());
+		storage.remove_from_storage(&prune60_65);
+		assert!(!storage.into_mdb().drain().is_empty());
 
-		// l1-digest is created every 2 blocks
-		// we want keep 2 additional changes tries
-		let config = Configuration { digest_interval: 2, digest_levels: 1 };
 		let storage = prepare_storage();
-		assert!(prune_by_collect(&config, &storage, 4, 69).is_empty());
-		let non_empty = prune_by_collect(&config, &storage, 4, 70);
-		assert!(!non_empty.is_empty());
-		storage.remove_from_storage(&non_empty);
-		assert!(prune_by_collect(&config, &storage, 4, 71).is_empty());
-		let non_empty = prune_by_collect(&config, &storage, 4, 72);
-		assert!(!non_empty.is_empty());
-		storage.remove_from_storage(&non_empty);
+		let prune60_70 = prune_by_collect(&storage, 60, 70, 90);
+		assert!(!prune60_70.is_empty());
+		storage.remove_from_storage(&prune60_70);
 		assert!(storage.into_mdb().drain().is_empty());
 	}
-
-	#[test]
-	fn pruning_range_works() {
-		// DIGESTS ARE NOT CREATED + NO TRIES ARE PRUNED
-		assert_eq!(pruning_range(&config(10, 0), 2u64, 2u64), None);
-
-		// DIGESTS ARE NOT CREATED + SOME TRIES ARE PRUNED
-		assert_eq!(pruning_range(&config(10, 0), 100u64, 110u64), Some((10, 10)));
-		assert_eq!(pruning_range(&config(10, 0), 100u64, 210u64), Some((110, 110)));
-
-		// DIGESTS ARE CREATED + NO TRIES ARE PRUNED
-
-		assert_eq!(pruning_range(&config(10, 2), 2u64, 0u64), None);
-		assert_eq!(pruning_range(&config(10, 2), 30u64, 100u64), None);
-		assert_eq!(pruning_range(&config(::std::u32::MAX, 2), 1u64, 1024u64), None);
-		assert_eq!(pruning_range(&config(::std::u32::MAX, 2), ::std::u64::MAX, 1024u64), None);
-		assert_eq!(pruning_range(&config(32, 2), 2048u64, 512u64), None);
-		assert_eq!(pruning_range(&config(32, 2), 2048u64, 1024u64), None);
-
-		// DIGESTS ARE CREATED + SOME TRIES ARE PRUNED
-
-		// when we do not want to keep any highest-level-digests
-		// (system forces to keep at least one)
-		assert_eq!(pruning_range(&config(4, 2), 0u64, 32u64), Some((1, 16)));
-		assert_eq!(pruning_range(&config(4, 2), 0u64, 64u64), Some((33, 48)));
-		// when we want to keep 1 (last) highest-level-digest
-		assert_eq!(pruning_range(&config(4, 2), 16u64, 32u64), Some((1, 16)));
-		assert_eq!(pruning_range(&config(4, 2), 16u64, 64u64), Some((33, 48)));
-		// when we want to keep 1 (last) + 1 additional level digests
-		assert_eq!(pruning_range(&config(32, 2), 4096u64, 5120u64), Some((1, 1024)));
-		assert_eq!(pruning_range(&config(32, 2), 4096u64, 6144u64), Some((1025, 2048)));
-	}
-
-	#[test]
-	fn max_digest_intervals_to_keep_works() {
-		assert_eq!(max_digest_intervals_to_keep(1024u64, 1025), 1u64);
-		assert_eq!(max_digest_intervals_to_keep(1024u64, 1023), 1u64);
-		assert_eq!(max_digest_intervals_to_keep(1024u64, 512), 2u64);
-		assert_eq!(max_digest_intervals_to_keep(1024u64, 511), 2u64);
-		assert_eq!(max_digest_intervals_to_keep(1024u64, 100), 10u64);
-	}
-
-	#[test]
-	fn oldest_non_pruned_trie_works() {
-		// when digests are not created at all
-		assert_eq!(oldest_non_pruned_trie(&config(0, 0), 100u64, 10u64), 1);
-		assert_eq!(oldest_non_pruned_trie(&config(0, 0), 100u64, 110u64), 11);
-
-		// when only l1 digests are created
-		assert_eq!(oldest_non_pruned_trie(&config(100, 1), 100u64, 50u64), 1);
-		assert_eq!(oldest_non_pruned_trie(&config(100, 1), 100u64, 110u64), 1);
-		assert_eq!(oldest_non_pruned_trie(&config(100, 1), 100u64, 210u64), 101);
-
-		// when l2 digests are created
-		assert_eq!(oldest_non_pruned_trie(&config(100, 2), 100u64, 50u64), 1);
-		assert_eq!(oldest_non_pruned_trie(&config(100, 2), 100u64, 110u64), 1);
-		assert_eq!(oldest_non_pruned_trie(&config(100, 2), 100u64, 210u64), 1);
-		assert_eq!(oldest_non_pruned_trie(&config(100, 2), 100u64, 10110u64), 1);
-		assert_eq!(oldest_non_pruned_trie(&config(100, 2), 100u64, 20110u64), 10001);
-	}
 }
diff --git a/primitives/state-machine/src/changes_trie/storage.rs b/primitives/state-machine/src/changes_trie/storage.rs
index 163ea7f412251..7fb418672872b 100644
--- a/primitives/state-machine/src/changes_trie/storage.rs
+++ b/primitives/state-machine/src/changes_trie/storage.rs
@@ -21,8 +21,11 @@ use hash_db::{Hasher, Prefix, EMPTY_PREFIX};
 use sp_trie::DBValue;
 use sp_trie::MemoryDB;
 use parking_lot::RwLock;
-use crate::changes_trie::{BuildCache, RootsStorage, Storage, AnchorBlockId, BlockNumber};
-use crate::trie_backend_essence::TrieBackendStorage;
+use crate::{
+	StorageKey,
+	trie_backend_essence::TrieBackendStorage,
+	changes_trie::{BuildCache, RootsStorage, Storage, AnchorBlockId, BlockNumber},
+};
 
 #[cfg(test)]
 use crate::backend::insert_into_memory_db;
@@ -93,7 +96,7 @@ impl<H: Hasher, Number: BlockNumber> InMemoryStorage<H, Number> {
 	#[cfg(test)]
 	pub fn with_inputs(
 		mut top_inputs: Vec<(Number, Vec<InputPair<Number>>)>,
-		children_inputs: Vec<(Vec<u8>, Vec<(Number, Vec<InputPair<Number>>)>)>,
+		children_inputs: Vec<(StorageKey, Vec<(Number, Vec<InputPair<Number>>)>)>,
 	) -> Self {
 		let mut mdb = MemoryDB::default();
 		let mut roots = BTreeMap::new();
@@ -179,7 +182,7 @@ impl<H: Hasher, Number: BlockNumber> Storage<H, Number> for InMemoryStorage<H, N
 	fn with_cached_changed_keys(
 		&self,
 		root: &H::Out,
-		functor: &mut dyn FnMut(&HashMap<Option<Vec<u8>>, HashSet<Vec<u8>>>),
+		functor: &mut dyn FnMut(&HashMap<Option<StorageKey>, HashSet<StorageKey>>),
 	) -> bool {
 		self.cache.with_changed_keys(root, functor)
 	}
diff --git a/primitives/state-machine/src/ext.rs b/primitives/state-machine/src/ext.rs
index 6fc4312d1079d..f293ae9f51615 100644
--- a/primitives/state-machine/src/ext.rs
+++ b/primitives/state-machine/src/ext.rs
@@ -17,8 +17,9 @@
 //! Concrete externalities implementation.
 
 use crate::{
-	backend::Backend, OverlayedChanges, StorageTransactionCache,
-	changes_trie::Storage as ChangesTrieStorage,
+	StorageKey, StorageValue, OverlayedChanges, StorageTransactionCache,
+	backend::Backend,
+	changes_trie::State as ChangesTrieState,
 };
 
 use hash_db::Hasher;
@@ -65,7 +66,7 @@ impl<B: error::Error, E: error::Error> error::Error for Error<B, E> {
 }
 
 /// Wraps a read-only backend, call executor, and current overlayed changes.
-pub struct Ext<'a, H, N, B, T>
+pub struct Ext<'a, H, N, B>
 	where
 		H: Hasher,
 		B: 'a + Backend<H>,
@@ -77,8 +78,8 @@ pub struct Ext<'a, H, N, B, T>
 	backend: &'a B,
 	/// The cache for the storage transactions.
 	storage_transaction_cache: &'a mut StorageTransactionCache<B::Transaction, H, N>,
-	/// Changes trie storage to read from.
-	changes_trie_storage: Option<&'a T>,
+	/// Changes trie state to read from.
+	changes_trie_state: Option<ChangesTrieState<'a, H, N>>,
 	/// Pseudo-unique id used for tracing.
 	pub id: u16,
 	/// Dummy usage of N arg.
@@ -87,12 +88,11 @@ pub struct Ext<'a, H, N, B, T>
 	extensions: Option<&'a mut Extensions>,
 }
 
-impl<'a, H, N, B, T> Ext<'a, H, N, B, T>
+impl<'a, H, N, B> Ext<'a, H, N, B>
 where
 	H: Hasher,
 	H::Out: Ord + 'static + codec::Codec,
 	B: 'a + Backend<H>,
-	T: 'a + ChangesTrieStorage<H, N>,
 	N: crate::changes_trie::BlockNumber,
 {
 
@@ -101,13 +101,13 @@ where
 		overlay: &'a mut OverlayedChanges,
 		storage_transaction_cache: &'a mut StorageTransactionCache<B::Transaction, H, N>,
 		backend: &'a B,
-		changes_trie_storage: Option<&'a T>,
+		changes_trie_state: Option<ChangesTrieState<'a, H, N>>,
 		extensions: Option<&'a mut Extensions>,
 	) -> Self {
 		Ext {
 			overlay,
 			backend,
-			changes_trie_storage,
+			changes_trie_state,
 			storage_transaction_cache,
 			id: rand::random(),
 			_phantom: Default::default(),
@@ -124,15 +124,14 @@ where
 }
 
 #[cfg(test)]
-impl<'a, H, N, B, T> Ext<'a, H, N, B, T>
+impl<'a, H, N, B> Ext<'a, H, N, B>
 where
 	H: Hasher,
 	H::Out: Ord + 'static,
 	B: 'a + Backend<H>,
-	T: 'a + ChangesTrieStorage<H, N>,
 	N: crate::changes_trie::BlockNumber,
 {
-	pub fn storage_pairs(&self) -> Vec<(Vec<u8>, Vec<u8>)> {
+	pub fn storage_pairs(&self) -> Vec<(StorageKey, StorageValue)> {
 		use std::collections::HashMap;
 
 		self.backend.pairs().iter()
@@ -146,15 +145,14 @@ where
 	}
 }
 
-impl<'a, H, B, T, N> Externalities for Ext<'a, H, N, B, T>
+impl<'a, H, B, N> Externalities for Ext<'a, H, N, B>
 where
 	H: Hasher,
 	H::Out: Ord + 'static + codec::Codec,
 	B: 'a + Backend<H>,
-	T: 'a + ChangesTrieStorage<H, N>,
 	N: crate::changes_trie::BlockNumber,
 {
-	fn storage(&self, key: &[u8]) -> Option<Vec<u8>> {
+	fn storage(&self, key: &[u8]) -> Option<StorageValue> {
 		let _guard = sp_panic_handler::AbortGuard::force_abort();
 		let result = self.overlay.storage(key).map(|x| x.map(|x| x.to_vec())).unwrap_or_else(||
 			self.backend.storage(key).expect(EXT_NOT_ALLOWED_TO_FAIL));
@@ -181,7 +179,7 @@ where
 		result.map(|r| r.encode())
 	}
 
-	fn original_storage(&self, key: &[u8]) -> Option<Vec<u8>> {
+	fn original_storage(&self, key: &[u8]) -> Option<StorageValue> {
 		let _guard = sp_panic_handler::AbortGuard::force_abort();
 		let result = self.backend.storage(key).expect(EXT_NOT_ALLOWED_TO_FAIL);
 
@@ -210,7 +208,7 @@ where
 		storage_key: ChildStorageKey,
 		child_info: ChildInfo,
 		key: &[u8],
-	) -> Option<Vec<u8>> {
+	) -> Option<StorageValue> {
 		let _guard = sp_panic_handler::AbortGuard::force_abort();
 		let result = self.overlay
 			.child_storage(storage_key.as_ref(), key)
@@ -259,7 +257,7 @@ where
 		storage_key: ChildStorageKey,
 		child_info: ChildInfo,
 		key: &[u8],
-	) -> Option<Vec<u8>> {
+	) -> Option<StorageValue> {
 		let _guard = sp_panic_handler::AbortGuard::force_abort();
 		let result = self.backend
 			.child_storage(storage_key.as_ref(), child_info, key)
@@ -335,7 +333,7 @@ where
 		result
 	}
 
-	fn next_storage_key(&self, key: &[u8]) -> Option<Vec<u8>> {
+	fn next_storage_key(&self, key: &[u8]) -> Option<StorageKey> {
 		let next_backend_key = self.backend.next_storage_key(key).expect(EXT_NOT_ALLOWED_TO_FAIL);
 		let next_overlay_key_change = self.overlay.next_storage_key_change(key);
 
@@ -355,7 +353,7 @@ where
 		storage_key: ChildStorageKey,
 		child_info: ChildInfo,
 		key: &[u8],
-	) -> Option<Vec<u8>> {
+	) -> Option<StorageKey> {
 		let next_backend_key = self.backend
 			.next_child_storage_key(storage_key.as_ref(), child_info, key)
 			.expect(EXT_NOT_ALLOWED_TO_FAIL);
@@ -379,7 +377,7 @@ where
 		}
 	}
 
-	fn place_storage(&mut self, key: Vec<u8>, value: Option<Vec<u8>>) {
+	fn place_storage(&mut self, key: StorageKey, value: Option<StorageValue>) {
 		trace!(target: "state-trace", "{:04x}: Put {}={:?}",
 			self.id,
 			HexDisplay::from(&key),
@@ -399,8 +397,8 @@ where
 		&mut self,
 		storage_key: ChildStorageKey,
 		child_info: ChildInfo,
-		key: Vec<u8>,
-		value: Option<Vec<u8>>,
+		key: StorageKey,
+		value: Option<StorageValue>,
 	) {
 		trace!(target: "state-trace", "{:04x}: PutChild({}) {}={:?}",
 			self.id,
@@ -564,7 +562,7 @@ where
 		let _guard = sp_panic_handler::AbortGuard::force_abort();
 		let root = self.overlay.changes_trie_root(
 			self.backend,
-			self.changes_trie_storage.clone(),
+			self.changes_trie_state.as_ref(),
 			Decode::decode(&mut &parent_hash[..]).map_err(|e|
 				trace!(
 					target: "state-trace",
@@ -586,11 +584,10 @@ where
 	}
 }
 
-impl<'a, H, B, T, N> sp_externalities::ExtensionStore for Ext<'a, H, N, B, T>
+impl<'a, H, B, N> sp_externalities::ExtensionStore for Ext<'a, H, N, B>
 where
 	H: Hasher,
 	B: 'a + Backend<H>,
-	T: 'a + ChangesTrieStorage<H, N>,
 	N: crate::changes_trie::BlockNumber,
 {
 	fn extension_by_type_id(&mut self, type_id: TypeId) -> Option<&mut dyn Any> {
@@ -602,19 +599,19 @@ where
 mod tests {
 	use super::*;
 	use hex_literal::hex;
+	use num_traits::Zero;
 	use codec::Encode;
 	use sp_core::{H256, Blake2Hasher, storage::well_known_keys::EXTRINSIC_INDEX, map};
 	use crate::{
 		changes_trie::{
 			Configuration as ChangesTrieConfiguration,
-			InMemoryStorage as InMemoryChangesTrieStorage,
+			InMemoryStorage as TestChangesTrieStorage,
 		}, InMemoryBackend, overlayed_changes::OverlayedValue,
 	};
 	use sp_core::storage::{Storage, StorageChild};
 
 	type TestBackend = InMemoryBackend<Blake2Hasher>;
-	type TestChangesTrieStorage = InMemoryChangesTrieStorage<Blake2Hasher, u64>;
-	type TestExt<'a> = Ext<'a, Blake2Hasher, u64, TestBackend, TestChangesTrieStorage>;
+	type TestExt<'a> = Ext<'a, Blake2Hasher, u64, TestBackend>;
 
 	fn prepare_overlay_with_changes() -> OverlayedChanges {
 		OverlayedChanges {
@@ -629,10 +626,14 @@ mod tests {
 				}),
 			].into_iter().collect(),
 			committed: Default::default(),
-			changes_trie_config: Some(ChangesTrieConfiguration {
-				digest_interval: 0,
-				digest_levels: 0,
-			}),
+			collect_extrinsics: true,
+		}
+	}
+
+	fn changes_trie_config() -> ChangesTrieConfiguration {
+		ChangesTrieConfiguration {
+			digest_interval: 0,
+			digest_levels: 0,
 		}
 	}
 
@@ -646,13 +647,11 @@ mod tests {
 	}
 
 	#[test]
-	fn storage_changes_root_is_none_when_extrinsic_changes_are_none() {
+	fn storage_changes_root_is_none_when_state_is_not_provided() {
 		let mut overlay = prepare_overlay_with_changes();
 		let mut cache = StorageTransactionCache::default();
-		overlay.changes_trie_config = None;
-		let storage = TestChangesTrieStorage::with_blocks(vec![(100, Default::default())]);
 		let backend = TestBackend::default();
-		let mut ext = TestExt::new(&mut overlay, &mut cache, &backend, Some(&storage), None);
+		let mut ext = TestExt::new(&mut overlay, &mut cache, &backend, None, None);
 		assert_eq!(ext.storage_changes_root(&H256::default().encode()).unwrap(), None);
 	}
 
@@ -661,8 +660,9 @@ mod tests {
 		let mut overlay = prepare_overlay_with_changes();
 		let mut cache = StorageTransactionCache::default();
 		let storage = TestChangesTrieStorage::with_blocks(vec![(99, Default::default())]);
+		let state = Some(ChangesTrieState::new(changes_trie_config(), Zero::zero(), &storage));
 		let backend = TestBackend::default();
-		let mut ext = TestExt::new(&mut overlay, &mut cache, &backend, Some(&storage), None);
+		let mut ext = TestExt::new(&mut overlay, &mut cache, &backend, state, None);
 		assert_eq!(
 			ext.storage_changes_root(&H256::default().encode()).unwrap(),
 			Some(hex!("bb0c2ef6e1d36d5490f9766cfcc7dfe2a6ca804504c3bb206053890d6dd02376").to_vec()),
@@ -675,8 +675,9 @@ mod tests {
 		let mut cache = StorageTransactionCache::default();
 		overlay.prospective.top.get_mut(&vec![1]).unwrap().value = None;
 		let storage = TestChangesTrieStorage::with_blocks(vec![(99, Default::default())]);
+		let state = Some(ChangesTrieState::new(changes_trie_config(), Zero::zero(), &storage));
 		let backend = TestBackend::default();
-		let mut ext = TestExt::new(&mut overlay, &mut cache, &backend, Some(&storage), None);
+		let mut ext = TestExt::new(&mut overlay, &mut cache, &backend, state, None);
 		assert_eq!(
 			ext.storage_changes_root(&H256::default().encode()).unwrap(),
 			Some(hex!("96f5aae4690e7302737b6f9b7f8567d5bbb9eac1c315f80101235a92d9ec27f4").to_vec()),
diff --git a/primitives/state-machine/src/in_memory_backend.rs b/primitives/state-machine/src/in_memory_backend.rs
index ae1a214a72c92..0a29468bbc4ef 100644
--- a/primitives/state-machine/src/in_memory_backend.rs
+++ b/primitives/state-machine/src/in_memory_backend.rs
@@ -16,7 +16,11 @@
 
 //! State machine in memory backend.
 
-use crate::{trie_backend::TrieBackend, backend::{Backend, insert_into_memory_db}};
+use crate::{
+	StorageKey, StorageValue, StorageCollection,
+	trie_backend::TrieBackend,
+	backend::{Backend, insert_into_memory_db},
+};
 use std::{error, fmt, collections::{BTreeMap, HashMap}, marker::PhantomData, ops};
 use hash_db::Hasher;
 use sp_trie::{
@@ -43,7 +47,7 @@ impl error::Error for Void {
 /// In-memory backend. Fully recomputes tries each time `as_trie_backend` is called but useful for
 /// tests and proof checking.
 pub struct InMemory<H: Hasher> {
-	inner: HashMap<Option<(Vec<u8>, OwnedChildInfo)>, BTreeMap<Vec<u8>, Vec<u8>>>,
+	inner: HashMap<Option<(StorageKey, OwnedChildInfo)>, BTreeMap<StorageKey, StorageValue>>,
 	// This field is only needed for returning reference in `as_trie_backend`.
 	trie: Option<TrieBackend<MemoryDB<H>, H>>,
 	_hasher: PhantomData<H>,
@@ -84,7 +88,7 @@ impl<H: Hasher> PartialEq for InMemory<H> {
 impl<H: Hasher> InMemory<H> {
 	/// Copy the state, with applied updates
 	pub fn update<
-		T: IntoIterator<Item = (Option<(Vec<u8>, OwnedChildInfo)>, Vec<(Vec<u8>, Option<Vec<u8>>)>)>
+		T: IntoIterator<Item = (Option<(StorageKey, OwnedChildInfo)>, StorageCollection)>
 	>(
 		&self,
 		changes: T,
@@ -103,10 +107,10 @@ impl<H: Hasher> InMemory<H> {
 	}
 }
 
-impl<H: Hasher> From<HashMap<Option<(Vec<u8>, OwnedChildInfo)>, BTreeMap<Vec<u8>, Vec<u8>>>>
+impl<H: Hasher> From<HashMap<Option<(StorageKey, OwnedChildInfo)>, BTreeMap<StorageKey, StorageValue>>>
 	for InMemory<H>
 {
-	fn from(inner: HashMap<Option<(Vec<u8>, OwnedChildInfo)>, BTreeMap<Vec<u8>, Vec<u8>>>) -> Self {
+	fn from(inner: HashMap<Option<(StorageKey, OwnedChildInfo)>, BTreeMap<StorageKey, StorageValue>>) -> Self {
 		InMemory {
 			inner,
 			trie: None,
@@ -117,7 +121,7 @@ impl<H: Hasher> From<HashMap<Option<(Vec<u8>, OwnedChildInfo)>, BTreeMap<Vec<u8>
 
 impl<H: Hasher> From<Storage> for InMemory<H> {
 	fn from(inners: Storage) -> Self {
-		let mut inner: HashMap<Option<(Vec<u8>, OwnedChildInfo)>, BTreeMap<Vec<u8>, Vec<u8>>>
+		let mut inner: HashMap<Option<(StorageKey, OwnedChildInfo)>, BTreeMap<StorageKey, StorageValue>>
 			= inners.children.into_iter().map(|(k, c)| (Some((k, c.child_info)), c.data)).collect();
 		inner.insert(None, inners.top);
 		InMemory {
@@ -128,8 +132,8 @@ impl<H: Hasher> From<Storage> for InMemory<H> {
 	}
 }
 
-impl<H: Hasher> From<BTreeMap<Vec<u8>, Vec<u8>>> for InMemory<H> {
-	fn from(inner: BTreeMap<Vec<u8>, Vec<u8>>) -> Self {
+impl<H: Hasher> From<BTreeMap<StorageKey, StorageValue>> for InMemory<H> {
+	fn from(inner: BTreeMap<StorageKey, StorageValue>) -> Self {
 		let mut expanded = HashMap::new();
 		expanded.insert(None, inner);
 		InMemory {
@@ -140,12 +144,12 @@ impl<H: Hasher> From<BTreeMap<Vec<u8>, Vec<u8>>> for InMemory<H> {
 	}
 }
 
-impl<H: Hasher> From<Vec<(Option<(Vec<u8>, OwnedChildInfo)>, Vec<(Vec<u8>, Option<Vec<u8>>)>)>>
+impl<H: Hasher> From<Vec<(Option<(StorageKey, OwnedChildInfo)>, StorageCollection)>>
 	for InMemory<H> {
 	fn from(
-		inner: Vec<(Option<(Vec<u8>, OwnedChildInfo)>, Vec<(Vec<u8>, Option<Vec<u8>>)>)>,
+		inner: Vec<(Option<(StorageKey, OwnedChildInfo)>, StorageCollection)>,
 	) -> Self {
-		let mut expanded: HashMap<Option<(Vec<u8>, OwnedChildInfo)>, BTreeMap<Vec<u8>, Vec<u8>>>
+		let mut expanded: HashMap<Option<(StorageKey, OwnedChildInfo)>, BTreeMap<StorageKey, StorageValue>>
 			= HashMap::new();
 		for (child_info, key_values) in inner {
 			let entry = expanded.entry(child_info).or_default();
@@ -171,12 +175,12 @@ impl<H: Hasher> InMemory<H> {
 impl<H: Hasher> Backend<H> for InMemory<H> where H::Out: Codec {
 	type Error = Void;
 	type Transaction = Vec<(
-		Option<(Vec<u8>, OwnedChildInfo)>,
-		Vec<(Vec<u8>, Option<Vec<u8>>)>,
+		Option<(StorageKey, OwnedChildInfo)>,
+		StorageCollection,
 	)>;
 	type TrieBackendStorage = MemoryDB<H>;
 
-	fn storage(&self, key: &[u8]) -> Result<Option<Vec<u8>>, Self::Error> {
+	fn storage(&self, key: &[u8]) -> Result<Option<StorageValue>, Self::Error> {
 		Ok(self.inner.get(&None).and_then(|map| map.get(key).map(Clone::clone)))
 	}
 
@@ -185,7 +189,7 @@ impl<H: Hasher> Backend<H> for InMemory<H> where H::Out: Codec {
 		storage_key: &[u8],
 		child_info: ChildInfo,
 		key: &[u8],
-	) -> Result<Option<Vec<u8>>, Self::Error> {
+	) -> Result<Option<StorageValue>, Self::Error> {
 		Ok(self.inner.get(&Some((storage_key.to_vec(), child_info.to_owned())))
 			.and_then(|map| map.get(key).map(Clone::clone)))
 	}
@@ -279,7 +283,7 @@ impl<H: Hasher> Backend<H> for InMemory<H> where H::Out: Codec {
 		(root, is_default, vec![(child_info, full_transaction)])
 	}
 
-	fn next_storage_key(&self, key: &[u8]) -> Result<Option<Vec<u8>>, Self::Error> {
+	fn next_storage_key(&self, key: &[u8]) -> Result<Option<StorageKey>, Self::Error> {
 		let range = (ops::Bound::Excluded(key), ops::Bound::Unbounded);
 		let next_key = self.inner.get(&None)
 			.and_then(|map| map.range::<[u8], _>(range).next().map(|(k, _)| k).cloned());
@@ -292,7 +296,7 @@ impl<H: Hasher> Backend<H> for InMemory<H> where H::Out: Codec {
 		storage_key: &[u8],
 		child_info: ChildInfo,
 		key: &[u8],
-	) -> Result<Option<Vec<u8>>, Self::Error> {
+	) -> Result<Option<StorageKey>, Self::Error> {
 		let range = (ops::Bound::Excluded(key), ops::Bound::Unbounded);
 		let next_key = self.inner.get(&Some((storage_key.to_vec(), child_info.to_owned())))
 			.and_then(|map| map.range::<[u8], _>(range).next().map(|(k, _)| k).cloned());
@@ -300,14 +304,14 @@ impl<H: Hasher> Backend<H> for InMemory<H> where H::Out: Codec {
 		Ok(next_key)
 	}
 
-	fn pairs(&self) -> Vec<(Vec<u8>, Vec<u8>)> {
+	fn pairs(&self) -> Vec<(StorageKey, StorageValue)> {
 		self.inner.get(&None)
 			.into_iter()
 			.flat_map(|map| map.iter().map(|(k, v)| (k.clone(), v.clone())))
 			.collect()
 	}
 
-	fn keys(&self, prefix: &[u8]) -> Vec<Vec<u8>> {
+	fn keys(&self, prefix: &[u8]) -> Vec<StorageKey> {
 		self.inner.get(&None)
 			.into_iter()
 			.flat_map(|map| map.keys().filter(|k| k.starts_with(prefix)).cloned())
@@ -319,7 +323,7 @@ impl<H: Hasher> Backend<H> for InMemory<H> where H::Out: Codec {
 		storage_key: &[u8],
 		child_info: ChildInfo,
 		prefix: &[u8],
-	) -> Vec<Vec<u8>> {
+	) -> Vec<StorageKey> {
 		self.inner.get(&Some((storage_key.to_vec(), child_info.to_owned())))
 			.into_iter()
 			.flat_map(|map| map.keys().filter(|k| k.starts_with(prefix)).cloned())
diff --git a/primitives/state-machine/src/lib.rs b/primitives/state-machine/src/lib.rs
index c8329178c6c4d..bb62df6da4905 100644
--- a/primitives/state-machine/src/lib.rs
+++ b/primitives/state-machine/src/lib.rs
@@ -23,8 +23,8 @@ use log::{warn, trace};
 use hash_db::Hasher;
 use codec::{Decode, Encode, Codec};
 use sp_core::{
-	storage::{well_known_keys, ChildInfo}, NativeOrEncoded, NeverNativeValue,
-	traits::CodeExecutor, hexdisplay::HexDisplay
+	storage::ChildInfo, NativeOrEncoded, NeverNativeValue,
+	traits::{CodeExecutor, CallInWasmExt}, hexdisplay::HexDisplay,
 };
 use overlayed_changes::OverlayedChangeSet;
 use sp_externalities::Extensions;
@@ -49,18 +49,23 @@ pub use ext::Ext;
 pub use backend::Backend;
 pub use changes_trie::{
 	AnchorBlockId as ChangesTrieAnchorBlockId,
+	State as ChangesTrieState,
 	Storage as ChangesTrieStorage,
 	RootsStorage as ChangesTrieRootsStorage,
 	InMemoryStorage as InMemoryChangesTrieStorage,
 	BuildCache as ChangesTrieBuildCache,
 	CacheAction as ChangesTrieCacheAction,
 	ConfigurationRange as ChangesTrieConfigurationRange,
-	key_changes, key_changes_proof, key_changes_proof_check,
+	key_changes, key_changes_proof,
+	key_changes_proof_check, key_changes_proof_check_with_db,
 	prune as prune_changes_tries,
-	oldest_non_pruned_trie as oldest_non_pruned_changes_trie,
+	disabled_state as disabled_changes_trie_state,
 	BlockNumber as ChangesTrieBlockNumber,
 };
-pub use overlayed_changes::{OverlayedChanges, StorageChanges, StorageTransactionCache};
+pub use overlayed_changes::{
+	OverlayedChanges, StorageChanges, StorageTransactionCache, StorageKey, StorageValue,
+	StorageCollection, ChildStorageCollection,
+};
 pub use proving_backend::{
 	create_proof_check_backend, create_proof_check_backend_storage, merge_storage_proofs,
 	ProofRecorder, ProvingBackend, ProvingBackendRecorder, StorageProof,
@@ -171,7 +176,7 @@ fn always_untrusted_wasm<E, R: Decode>() -> ExecutionManager<DefaultHandler<R, E
 }
 
 /// The substrate state machine.
-pub struct StateMachine<'a, B, H, N, T, Exec>
+pub struct StateMachine<'a, B, H, N, Exec>
 	where
 		H: Hasher,
 		B: Backend<H>,
@@ -183,29 +188,30 @@ pub struct StateMachine<'a, B, H, N, T, Exec>
 	call_data: &'a [u8],
 	overlay: &'a mut OverlayedChanges,
 	extensions: Extensions,
-	changes_trie_storage: Option<&'a T>,
+	changes_trie_state: Option<ChangesTrieState<'a, H, N>>,
 	_marker: PhantomData<(H, N)>,
 	storage_transaction_cache: Option<&'a mut StorageTransactionCache<B::Transaction, H, N>>,
 }
 
-impl<'a, B, H, N, T, Exec> StateMachine<'a, B, H, N, T, Exec> where
+impl<'a, B, H, N, Exec> StateMachine<'a, B, H, N, Exec> where
 	H: Hasher,
 	H::Out: Ord + 'static + codec::Codec,
-	Exec: CodeExecutor,
+	Exec: CodeExecutor + Clone + 'static,
 	B: Backend<H>,
-	T: ChangesTrieStorage<H, N>,
 	N: crate::changes_trie::BlockNumber,
 {
 	/// Creates new substrate state machine.
 	pub fn new(
 		backend: &'a B,
-		changes_trie_storage: Option<&'a T>,
+		changes_trie_state: Option<ChangesTrieState<'a, H, N>>,
 		overlay: &'a mut OverlayedChanges,
 		exec: &'a Exec,
 		method: &'a str,
 		call_data: &'a [u8],
-		extensions: Extensions,
+		mut extensions: Extensions,
 	) -> Self {
+		extensions.register(CallInWasmExt::new(exec.clone()));
+
 		Self {
 			backend,
 			exec,
@@ -213,7 +219,7 @@ impl<'a, B, H, N, T, Exec> StateMachine<'a, B, H, N, T, Exec> where
 			call_data,
 			extensions,
 			overlay,
-			changes_trie_storage,
+			changes_trie_state,
 			_marker: PhantomData,
 			storage_transaction_cache: None,
 		}
@@ -271,7 +277,7 @@ impl<'a, B, H, N, T, Exec> StateMachine<'a, B, H, N, T, Exec> where
 			self.overlay,
 			cache,
 			self.backend,
-			self.changes_trie_storage.clone(),
+			self.changes_trie_state.clone(),
 			Some(&mut self.extensions),
 		);
 
@@ -386,20 +392,8 @@ impl<'a, B, H, N, T, Exec> StateMachine<'a, B, H, N, T, Exec> where
 				CallResult<R, Exec::Error>,
 			) -> CallResult<R, Exec::Error>
 	{
-		// read changes trie configuration. The reason why we're doing it here instead of the
-		// `OverlayedChanges` constructor is that we need proofs for this read as a part of
-		// proof-of-execution on light clients. And the proof is recorded by the backend which
-		// is created after OverlayedChanges
-
-		let init_overlay = |overlay: &mut OverlayedChanges, final_check: bool, backend: &B| {
-			let changes_trie_config = try_read_overlay_value(
-				overlay,
-				backend,
-				well_known_keys::CHANGES_TRIE_CONFIG
-			)?;
-			set_changes_trie_config(overlay, changes_trie_config, final_check)
-		};
-		init_overlay(self.overlay, false, &self.backend)?;
+		let changes_tries_enabled = self.changes_trie_state.is_some();
+		self.overlay.set_collect_extrinsics(changes_tries_enabled);
 
 		let result = {
 			let orig_prospective = self.overlay.prospective.clone();
@@ -431,16 +425,12 @@ impl<'a, B, H, N, T, Exec> StateMachine<'a, B, H, N, T, Exec> where
 			}
 		};
 
-		if result.is_ok() {
-			init_overlay(self.overlay, true, self.backend)?;
-		}
-
 		result.map_err(|e| Box::new(e) as _)
 	}
 }
 
 /// Prove execution using the given state backend, overlayed changes, and call executor.
-pub fn prove_execution<B, H, Exec>(
+pub fn prove_execution<B, H, N, Exec>(
 	mut backend: B,
 	overlay: &mut OverlayedChanges,
 	exec: &Exec,
@@ -451,11 +441,12 @@ where
 	B: Backend<H>,
 	H: Hasher,
 	H::Out: Ord + 'static + codec::Codec,
-	Exec: CodeExecutor,
+	Exec: CodeExecutor + Clone + 'static,
+	N: crate::changes_trie::BlockNumber,
 {
 	let trie_backend = backend.as_trie_backend()
 		.ok_or_else(|| Box::new(ExecutionError::UnableToGenerateProof) as Box<dyn Error>)?;
-	prove_execution_on_trie_backend(trie_backend, overlay, exec, method, call_data)
+	prove_execution_on_trie_backend::<_, _, N, _>(trie_backend, overlay, exec, method, call_data)
 }
 
 /// Prove execution using the given trie backend, overlayed changes, and call executor.
@@ -467,7 +458,7 @@ where
 ///
 /// Note: changes to code will be in place if this call is made again. For running partial
 /// blocks (e.g. a transaction at a time), ensure a different method is used.
-pub fn prove_execution_on_trie_backend<S, H, Exec>(
+pub fn prove_execution_on_trie_backend<S, H, N, Exec>(
 	trie_backend: &TrieBackend<S, H>,
 	overlay: &mut OverlayedChanges,
 	exec: &Exec,
@@ -478,10 +469,11 @@ where
 	S: trie_backend_essence::TrieBackendStorage<H>,
 	H: Hasher,
 	H::Out: Ord + 'static + codec::Codec,
-	Exec: CodeExecutor,
+	Exec: CodeExecutor + 'static + Clone,
+	N: crate::changes_trie::BlockNumber,
 {
 	let proving_backend = proving_backend::ProvingBackend::new(trie_backend);
-	let mut sm = StateMachine::<_, H, _, InMemoryChangesTrieStorage<H, u64>, Exec>::new(
+	let mut sm = StateMachine::<_, H, N, Exec>::new(
 		&proving_backend, None, overlay, exec, method, call_data, Extensions::default(),
 	);
 
@@ -494,7 +486,7 @@ where
 }
 
 /// Check execution proof, generated by `prove_execution` call.
-pub fn execution_proof_check<H, Exec>(
+pub fn execution_proof_check<H, N, Exec>(
 	root: H::Out,
 	proof: StorageProof,
 	overlay: &mut OverlayedChanges,
@@ -504,15 +496,16 @@ pub fn execution_proof_check<H, Exec>(
 ) -> Result<Vec<u8>, Box<dyn Error>>
 where
 	H: Hasher,
-	Exec: CodeExecutor,
+	Exec: CodeExecutor + Clone + 'static,
 	H::Out: Ord + 'static + codec::Codec,
+	N: crate::changes_trie::BlockNumber,
 {
 	let trie_backend = create_proof_check_backend::<H>(root.into(), proof)?;
-	execution_proof_check_on_trie_backend(&trie_backend, overlay, exec, method, call_data)
+	execution_proof_check_on_trie_backend::<_, N, _>(&trie_backend, overlay, exec, method, call_data)
 }
 
 /// Check execution proof on proving backend, generated by `prove_execution` call.
-pub fn execution_proof_check_on_trie_backend<H, Exec>(
+pub fn execution_proof_check_on_trie_backend<H, N, Exec>(
 	trie_backend: &TrieBackend<MemoryDB<H>, H>,
 	overlay: &mut OverlayedChanges,
 	exec: &Exec,
@@ -522,9 +515,10 @@ pub fn execution_proof_check_on_trie_backend<H, Exec>(
 where
 	H: Hasher,
 	H::Out: Ord + 'static + codec::Codec,
-	Exec: CodeExecutor,
+	Exec: CodeExecutor + Clone + 'static,
+	N: crate::changes_trie::BlockNumber,
 {
-	let mut sm = StateMachine::<_, H, _, InMemoryChangesTrieStorage<H, u64>, Exec>::new(
+	let mut sm = StateMachine::<_, H, N, Exec>::new(
 		trie_backend, None, overlay, exec, method, call_data, Extensions::default(),
 	);
 
@@ -690,44 +684,6 @@ where
 		.map_err(|e| Box::new(e) as Box<dyn Error>)
 }
 
-/// Sets overlayed changes' changes trie configuration. Returns error if configuration
-/// differs from previous OR config decode has failed.
-fn set_changes_trie_config(
-	overlay: &mut OverlayedChanges,
-	config: Option<Vec<u8>>,
-	final_check: bool,
-) -> Result<(), Box<dyn Error>> {
-	let config = match config {
-		Some(v) => Some(Decode::decode(&mut &v[..])
-			.map_err(|_| Box::new("Failed to decode changes trie configuration".to_owned()) as Box<dyn Error>)?),
-		None => None,
-	};
-
-	if final_check && overlay.changes_trie_config.is_some() != config.is_some() {
-		return Err(Box::new("Changes trie configuration change is not supported".to_owned()));
-	}
-
-	if let Some(config) = config {
-		if !overlay.set_changes_trie_config(config) {
-			return Err(Box::new("Changes trie configuration change is not supported".to_owned()));
-		}
-	}
-	Ok(())
-}
-
-/// Reads storage value from overlay or from the backend.
-fn try_read_overlay_value<H, B>(
-	overlay: &OverlayedChanges,
-	backend: &B, key: &[u8],
-) -> Result<Option<Vec<u8>>, Box<dyn Error>> where H: Hasher, B: Backend<H> {
-	match overlay.storage(key).map(|x| x.map(|x| x.to_vec())) {
-		Some(value) => Ok(value),
-		None => backend
-			.storage(key)
-			.map_err(|err| Box::new(ExecutionError::Backend(format!("{}", err))) as Box<dyn Error>),
-	}
-}
-
 #[cfg(test)]
 mod tests {
 	use std::collections::BTreeMap;
@@ -735,12 +691,10 @@ mod tests {
 	use overlayed_changes::OverlayedValue;
 	use super::*;
 	use super::ext::Ext;
-	use super::changes_trie::{
-		InMemoryStorage as InMemoryChangesTrieStorage,
-		Configuration as ChangesTrieConfig,
-	};
+	use super::changes_trie::Configuration as ChangesTrieConfig;
 	use sp_core::{Blake2Hasher, map, traits::Externalities, storage::ChildStorageKey};
 
+	#[derive(Clone)]
 	struct DummyCodeExecutor {
 		change_changes_trie_config: bool,
 		native_available: bool,
@@ -767,7 +721,7 @@ mod tests {
 		) -> (CallResult<R, Self::Error>, bool) {
 			if self.change_changes_trie_config {
 				ext.place_storage(
-					well_known_keys::CHANGES_TRIE_CONFIG.to_vec(),
+					sp_core::storage::well_known_keys::CHANGES_TRIE_CONFIG.to_vec(),
 					Some(
 						ChangesTrieConfig {
 							digest_interval: 777,
@@ -797,15 +751,26 @@ mod tests {
 		}
 	}
 
+	impl sp_core::traits::CallInWasm for DummyCodeExecutor {
+		fn call_in_wasm(
+			&self,
+			_: &[u8],
+			_: &str,
+			_: &[u8],
+			_: &mut dyn Externalities,
+		) -> std::result::Result<Vec<u8>, String> {
+			unimplemented!("Not required in tests.")
+		}
+	}
+
 	#[test]
 	fn execute_works() {
 		let backend = trie_backend::tests::test_trie();
 		let mut overlayed_changes = Default::default();
-		let changes_trie_storage = InMemoryChangesTrieStorage::<Blake2Hasher, u64>::new();
 
 		let mut state_machine = StateMachine::new(
 			&backend,
-			Some(&changes_trie_storage),
+			changes_trie::disabled_state::<_, u64>(),
 			&mut overlayed_changes,
 			&DummyCodeExecutor {
 				change_changes_trie_config: false,
@@ -829,11 +794,10 @@ mod tests {
 	fn execute_works_with_native_else_wasm() {
 		let backend = trie_backend::tests::test_trie();
 		let mut overlayed_changes = Default::default();
-		let changes_trie_storage = InMemoryChangesTrieStorage::<Blake2Hasher, u64>::new();
 
 		let mut state_machine = StateMachine::new(
 			&backend,
-			Some(&changes_trie_storage),
+			changes_trie::disabled_state::<_, u64>(),
 			&mut overlayed_changes,
 			&DummyCodeExecutor {
 				change_changes_trie_config: false,
@@ -854,11 +818,10 @@ mod tests {
 		let mut consensus_failed = false;
 		let backend = trie_backend::tests::test_trie();
 		let mut overlayed_changes = Default::default();
-		let changes_trie_storage = InMemoryChangesTrieStorage::<Blake2Hasher, u64>::new();
 
 		let mut state_machine = StateMachine::new(
 			&backend,
-			Some(&changes_trie_storage),
+			changes_trie::disabled_state::<_, u64>(),
 			&mut overlayed_changes,
 			&DummyCodeExecutor {
 				change_changes_trie_config: false,
@@ -895,7 +858,7 @@ mod tests {
 		// fetch execution proof from 'remote' full node
 		let remote_backend = trie_backend::tests::test_trie();
 		let remote_root = remote_backend.storage_root(std::iter::empty()).0;
-		let (remote_result, remote_proof) = prove_execution(
+		let (remote_result, remote_proof) = prove_execution::<_, _, u64, _>(
 			remote_backend,
 			&mut Default::default(),
 			&executor,
@@ -904,7 +867,7 @@ mod tests {
 		).unwrap();
 
 		// check proof locally
-		let local_result = execution_proof_check::<Blake2Hasher, _>(
+		let local_result = execution_proof_check::<Blake2Hasher, u64, _>(
 			remote_root,
 			remote_proof,
 			&mut Default::default(),
@@ -941,13 +904,12 @@ mod tests {
 		};
 
 		{
-			let changes_trie_storage = InMemoryChangesTrieStorage::<Blake2Hasher, u64>::new();
 			let mut cache = StorageTransactionCache::default();
 			let mut ext = Ext::new(
 				&mut overlay,
 				&mut cache,
 				backend,
-				Some(&changes_trie_storage),
+				changes_trie::disabled_state::<_, u64>(),
 				None,
 			);
 			ext.clear_prefix(b"ab");
@@ -972,14 +934,13 @@ mod tests {
 	fn set_child_storage_works() {
 		let mut state = InMemoryBackend::<Blake2Hasher>::default();
 		let backend = state.as_trie_backend().unwrap();
-		let changes_trie_storage = InMemoryChangesTrieStorage::<Blake2Hasher, u64>::new();
 		let mut overlay = OverlayedChanges::default();
 		let mut cache = StorageTransactionCache::default();
 		let mut ext = Ext::new(
 			&mut overlay,
 			&mut cache,
 			backend,
-			Some(&changes_trie_storage),
+			changes_trie::disabled_state::<_, u64>(),
 			None,
 		);
 
@@ -1065,30 +1026,6 @@ mod tests {
 		);
 	}
 
-	#[test]
-	fn cannot_change_changes_trie_config() {
-		let backend = trie_backend::tests::test_trie();
-		let mut overlayed_changes = Default::default();
-		let changes_trie_storage = InMemoryChangesTrieStorage::<Blake2Hasher, u64>::new();
-
-		let mut state_machine = StateMachine::new(
-			&backend,
-			Some(&changes_trie_storage),
-			&mut overlayed_changes,
-			&DummyCodeExecutor {
-				change_changes_trie_config: true,
-				native_available: false,
-				native_succeeds: true,
-				fallback_succeeds: true,
-			},
-			"test",
-			&[],
-			Default::default(),
-		);
-
-		assert!(state_machine.execute(ExecutionStrategy::NativeWhenPossible).is_err());
-	}
-
 	#[test]
 	fn child_storage_uuid() {
 		const CHILD_INFO_1: ChildInfo<'static> = ChildInfo::new_default(b"unique_id_1");
@@ -1100,13 +1037,12 @@ mod tests {
 		let subtrie2 = ChildStorageKey::from_slice(b":child_storage:default:sub_test2").unwrap();
 		let mut transaction = {
 			let backend = test_trie();
-			let changes_trie_storage = InMemoryChangesTrieStorage::<Blake2Hasher, u64>::new();
 			let mut cache = StorageTransactionCache::default();
 			let mut ext = Ext::new(
 				&mut overlay,
 				&mut cache,
 				&backend,
-				Some(&changes_trie_storage),
+				changes_trie::disabled_state::<_, u64>(),
 				None,
 			);
 			ext.set_child_storage(subtrie1, CHILD_INFO_1, b"abc".to_vec(), b"def".to_vec());
@@ -1124,28 +1060,4 @@ mod tests {
 		}
 		assert!(!duplicate);
 	}
-
-	#[test]
-	fn cannot_change_changes_trie_config_with_native_else_wasm() {
-		let backend = trie_backend::tests::test_trie();
-		let mut overlayed_changes = Default::default();
-		let changes_trie_storage = InMemoryChangesTrieStorage::<Blake2Hasher, u64>::new();
-
-		let mut state_machine = StateMachine::new(
-			&backend,
-			Some(&changes_trie_storage),
-			&mut overlayed_changes,
-			&DummyCodeExecutor {
-				change_changes_trie_config: true,
-				native_available: false,
-				native_succeeds: true,
-				fallback_succeeds: true,
-			},
-			"test",
-			&[],
-			Default::default(),
-		);
-
-		assert!(state_machine.execute(ExecutionStrategy::NativeElseWasm).is_err());
-	}
 }
diff --git a/primitives/state-machine/src/overlayed_changes.rs b/primitives/state-machine/src/overlayed_changes.rs
index eafd31241038b..ed6f30a4f596b 100644
--- a/primitives/state-machine/src/overlayed_changes.rs
+++ b/primitives/state-machine/src/overlayed_changes.rs
@@ -19,8 +19,8 @@
 use crate::{
 	backend::Backend, ChangesTrieTransaction,
 	changes_trie::{
-		NO_EXTRINSIC_INDEX, Configuration as ChangesTrieConfig, BlockNumber, build_changes_trie,
-		Storage as ChangesTrieStorage,
+		NO_EXTRINSIC_INDEX, BlockNumber, build_changes_trie,
+		State as ChangesTrieState,
 	},
 };
 
@@ -33,6 +33,18 @@ use std::{mem, ops};
 
 use hash_db::Hasher;
 
+/// Storage key.
+pub type StorageKey = Vec<u8>;
+
+/// Storage value.
+pub type StorageValue = Vec<u8>;
+
+/// In memory array of storage values.
+pub type StorageCollection = Vec<(StorageKey, Option<StorageValue>)>;
+
+/// In memory arrays of storage values for multiple child tries.
+pub type ChildStorageCollection = Vec<(StorageKey, StorageCollection)>;
+
 /// The overlayed changes to state to be queried on top of the backend.
 ///
 /// A transaction shares all prospective changes within an inner overlay
@@ -43,9 +55,8 @@ pub struct OverlayedChanges {
 	pub(crate) prospective: OverlayedChangeSet,
 	/// Committed changes.
 	pub(crate) committed: OverlayedChangeSet,
-	/// Changes trie configuration. None by default, but could be installed by the
-	/// runtime if it supports change tries.
-	pub(crate) changes_trie_config: Option<ChangesTrieConfig>,
+	/// True if extrinsiscs stats must be collected.
+	pub(crate) collect_extrinsics: bool,
 }
 
 /// The storage value, used inside OverlayedChanges.
@@ -53,7 +64,7 @@ pub struct OverlayedChanges {
 #[cfg_attr(test, derive(PartialEq))]
 pub struct OverlayedValue {
 	/// Current value. None if value has been deleted.
-	pub value: Option<Vec<u8>>,
+	pub value: Option<StorageValue>,
 	/// The set of extinsic indices where the values has been changed.
 	/// Is filled only if runtime has announced changes trie support.
 	pub extrinsics: Option<BTreeSet<u32>>,
@@ -64,9 +75,9 @@ pub struct OverlayedValue {
 #[cfg_attr(test, derive(PartialEq))]
 pub struct OverlayedChangeSet {
 	/// Top level storage changes.
-	pub top: BTreeMap<Vec<u8>, OverlayedValue>,
+	pub top: BTreeMap<StorageKey, OverlayedValue>,
 	/// Child storage changes.
-	pub children: HashMap<Vec<u8>, (BTreeMap<Vec<u8>, OverlayedValue>, OwnedChildInfo)>,
+	pub children: HashMap<StorageKey, (BTreeMap<StorageKey, OverlayedValue>, OwnedChildInfo)>,
 }
 
 /// A storage changes structure that can be generated by the data collected in [`OverlayedChanges`].
@@ -77,9 +88,9 @@ pub struct StorageChanges<Transaction, H: Hasher, N: BlockNumber> {
 	/// All changes to the main storage.
 	///
 	/// A value of `None` means that it was deleted.
-	pub main_storage_changes: Vec<(Vec<u8>, Option<Vec<u8>>)>,
+	pub main_storage_changes: StorageCollection,
 	/// All changes to the child storages.
-	pub child_storage_changes: Vec<(Vec<u8>, Vec<(Vec<u8>, Option<Vec<u8>>)>)>,
+	pub child_storage_changes: ChildStorageCollection,
 	/// A transaction for the backend that contains all changes from
 	/// [`main_storage_changes`](Self::main_storage_changes) and from
 	/// [`child_storage_changes`](Self::child_storage_changes).
@@ -95,8 +106,8 @@ pub struct StorageChanges<Transaction, H: Hasher, N: BlockNumber> {
 impl<Transaction, H: Hasher, N: BlockNumber> StorageChanges<Transaction, H, N> {
 	/// Deconstruct into the inner values
 	pub fn into_inner(self) -> (
-		Vec<(Vec<u8>, Option<Vec<u8>>)>,
-		Vec<(Vec<u8>, Vec<(Vec<u8>, Option<Vec<u8>>)>)>,
+		StorageCollection,
+		ChildStorageCollection,
 		Transaction,
 		H::Out,
 		Option<ChangesTrieTransaction<H, N>>,
@@ -156,8 +167,8 @@ impl<Transaction: Default, H: Hasher, N: BlockNumber> Default for StorageChanges
 }
 
 #[cfg(test)]
-impl FromIterator<(Vec<u8>, OverlayedValue)> for OverlayedChangeSet {
-	fn from_iter<T: IntoIterator<Item = (Vec<u8>, OverlayedValue)>>(iter: T) -> Self {
+impl FromIterator<(StorageKey, OverlayedValue)> for OverlayedChangeSet {
+	fn from_iter<T: IntoIterator<Item = (StorageKey, OverlayedValue)>>(iter: T) -> Self {
 		Self {
 			top: iter.into_iter().collect(),
 			children: Default::default(),
@@ -184,20 +195,9 @@ impl OverlayedChanges {
 		self.prospective.is_empty() && self.committed.is_empty()
 	}
 
-	/// Sets the changes trie configuration.
-	///
-	/// Returns false if configuration has been set already and we now trying
-	/// to install different configuration. This isn't supported now.
-	pub(crate) fn set_changes_trie_config(&mut self, config: ChangesTrieConfig) -> bool {
-		if let Some(ref old_config) = self.changes_trie_config {
-			// we do not support changes trie configuration' change now
-			if *old_config != config {
-				return false;
-			}
-		}
-
-		self.changes_trie_config = Some(config);
-		true
+	/// Ask to collect/not to collect extrinsics indices where key(s) has been changed.
+	pub fn set_collect_extrinsics(&mut self, collect_extrinsics: bool) {
+		self.collect_extrinsics = collect_extrinsics;
 	}
 
 	/// Returns a double-Option: None if the key is unknown (i.e. and the query should be referred
@@ -231,7 +231,7 @@ impl OverlayedChanges {
 	/// Inserts the given key-value pair into the prospective change set.
 	///
 	/// `None` can be used to delete a value specified by the given key.
-	pub(crate) fn set_storage(&mut self, key: Vec<u8>, val: Option<Vec<u8>>) {
+	pub(crate) fn set_storage(&mut self, key: StorageKey, val: Option<StorageValue>) {
 		let extrinsic_index = self.extrinsic_index();
 		let entry = self.prospective.top.entry(key).or_default();
 		entry.value = val;
@@ -247,10 +247,10 @@ impl OverlayedChanges {
 	/// `None` can be used to delete a value specified by the given key.
 	pub(crate) fn set_child_storage(
 		&mut self,
-		storage_key: Vec<u8>,
+		storage_key: StorageKey,
 		child_info: ChildInfo,
-		key: Vec<u8>,
-		val: Option<Vec<u8>>,
+		key: StorageKey,
+		val: Option<StorageValue>,
 	) {
 		let extrinsic_index = self.extrinsic_index();
 		let map_entry = self.prospective.children.entry(storage_key)
@@ -429,8 +429,8 @@ impl OverlayedChanges {
 	/// Panics:
 	/// Will panic if there are any uncommitted prospective changes.
 	pub fn into_committed(self) -> (
-		impl Iterator<Item=(Vec<u8>, Option<Vec<u8>>)>,
-		impl Iterator<Item=(Vec<u8>, (impl Iterator<Item=(Vec<u8>, Option<Vec<u8>>)>, OwnedChildInfo))>,
+		impl Iterator<Item=(StorageKey, Option<StorageValue>)>,
+		impl Iterator<Item=(StorageKey, (impl Iterator<Item=(StorageKey, Option<StorageValue>)>, OwnedChildInfo))>,
 	){
 		assert!(self.prospective.is_empty());
 		(
@@ -442,11 +442,11 @@ impl OverlayedChanges {
 
 	/// Convert this instance with all changes into a [`StorageChanges`] instance.
 	pub fn into_storage_changes<
-		B: Backend<H>, H: Hasher, N: BlockNumber, T: ChangesTrieStorage<H, N>
+		B: Backend<H>, H: Hasher, N: BlockNumber
 	>(
 		self,
 		backend: &B,
-		changes_trie_storage: Option<&T>,
+		changes_trie_state: Option<&ChangesTrieState<H, N>>,
 		parent_hash: H::Out,
 		mut cache: StorageTransactionCache<B::Transaction, H, N>,
 	) -> Result<StorageChanges<B::Transaction, H, N>, String> where H::Out: Ord + Encode + 'static {
@@ -463,7 +463,7 @@ impl OverlayedChanges {
 		if cache.changes_trie_transaction.is_none() {
 			self.changes_trie_root(
 				backend,
-				changes_trie_storage,
+				changes_trie_state,
 				parent_hash,
 				false,
 				&mut cache,
@@ -501,7 +501,7 @@ impl OverlayedChanges {
 	/// Changes that are made outside of extrinsics, are marked with
 	/// `NO_EXTRINSIC_INDEX` index.
 	fn extrinsic_index(&self) -> Option<u32> {
-		match self.changes_trie_config.is_some() {
+		match self.collect_extrinsics {
 			true => Some(
 				self.storage(EXTRINSIC_INDEX)
 					.and_then(|idx| idx.and_then(|idx| Decode::decode(&mut &*idx).ok()))
@@ -557,17 +557,17 @@ impl OverlayedChanges {
 	/// # Panics
 	///
 	/// Panics on storage error, when `panic_on_storage_error` is set.
-	pub fn changes_trie_root<H: Hasher, N: BlockNumber, B: Backend<H>, T: ChangesTrieStorage<H, N>>(
+	pub fn changes_trie_root<'a, H: Hasher, N: BlockNumber, B: Backend<H>>(
 		&self,
 		backend: &B,
-		changes_trie_storage: Option<&T>,
+		changes_trie_state: Option<&'a ChangesTrieState<'a, H, N>>,
 		parent_hash: H::Out,
 		panic_on_storage_error: bool,
 		cache: &mut StorageTransactionCache<B::Transaction, H, N>,
 	) -> Result<Option<H::Out>, ()> where H::Out: Ord + Encode + 'static {
-		build_changes_trie::<_, T, H, N>(
+		build_changes_trie::<_, H, N>(
 			backend,
-			changes_trie_storage,
+			changes_trie_state,
 			self,
 			parent_hash,
 			panic_on_storage_error,
@@ -643,8 +643,8 @@ impl OverlayedChanges {
 }
 
 #[cfg(test)]
-impl From<Option<Vec<u8>>> for OverlayedValue {
-	fn from(value: Option<Vec<u8>>) -> OverlayedValue {
+impl From<Option<StorageValue>> for OverlayedValue {
+	fn from(value: Option<StorageValue>) -> OverlayedValue {
 		OverlayedValue { value, ..Default::default() }
 	}
 }
@@ -656,12 +656,11 @@ mod tests {
 		Blake2Hasher, traits::Externalities, storage::well_known_keys::EXTRINSIC_INDEX,
 	};
 	use crate::InMemoryBackend;
-	use crate::changes_trie::InMemoryStorage as InMemoryChangesTrieStorage;
 	use crate::ext::Ext;
 	use super::*;
 
-	fn strip_extrinsic_index(map: &BTreeMap<Vec<u8>, OverlayedValue>)
-		-> BTreeMap<Vec<u8>, OverlayedValue>
+	fn strip_extrinsic_index(map: &BTreeMap<StorageKey, OverlayedValue>)
+		-> BTreeMap<StorageKey, OverlayedValue>
 	{
 		let mut clone = map.clone();
 		clone.remove(&EXTRINSIC_INDEX.to_vec());
@@ -718,13 +717,12 @@ mod tests {
 			..Default::default()
 		};
 
-		let changes_trie_storage = InMemoryChangesTrieStorage::<Blake2Hasher, u64>::new();
 		let mut cache = StorageTransactionCache::default();
 		let mut ext = Ext::new(
 			&mut overlay,
 			&mut cache,
 			&backend,
-			Some(&changes_trie_storage),
+			crate::changes_trie::disabled_state::<_, u64>(),
 			None,
 		);
 		const ROOT: [u8; 32] = hex!("39245109cef3758c2eed2ccba8d9b370a917850af3824bc8348d505df2c298fa");
@@ -732,57 +730,10 @@ mod tests {
 		assert_eq!(&ext.storage_root()[..], &ROOT);
 	}
 
-	#[test]
-	fn changes_trie_configuration_is_saved() {
-		let mut overlay = OverlayedChanges::default();
-		assert!(overlay.changes_trie_config.is_none());
-		assert_eq!(
-			overlay.set_changes_trie_config(
-				ChangesTrieConfig { digest_interval: 4, digest_levels: 1, },
-			),
-			true,
-		);
-		assert!(overlay.changes_trie_config.is_some());
-	}
-
-	#[test]
-	fn changes_trie_configuration_is_saved_twice() {
-		let mut overlay = OverlayedChanges::default();
-		assert!(overlay.changes_trie_config.is_none());
-		assert_eq!(overlay.set_changes_trie_config(ChangesTrieConfig {
-			digest_interval: 4, digest_levels: 1,
-		}), true);
-		overlay.set_extrinsic_index(0);
-		overlay.set_storage(vec![1], Some(vec![2]));
-		assert_eq!(overlay.set_changes_trie_config(ChangesTrieConfig {
-			digest_interval: 4, digest_levels: 1,
-		}), true);
-		assert_eq!(
-			strip_extrinsic_index(&overlay.prospective.top),
-			vec![
-				(vec![1], OverlayedValue { value: Some(vec![2]),
-				 extrinsics: Some(vec![0].into_iter().collect()) }),
-			].into_iter().collect(),
-		);
-	}
-
-	#[test]
-	fn panics_when_trying_to_save_different_changes_trie_configuration() {
-		let mut overlay = OverlayedChanges::default();
-		assert_eq!(overlay.set_changes_trie_config(ChangesTrieConfig {
-			digest_interval: 4, digest_levels: 1,
-		}), true);
-		assert_eq!(overlay.set_changes_trie_config(ChangesTrieConfig {
-			digest_interval: 2, digest_levels: 1,
-		}), false);
-	}
-
 	#[test]
 	fn extrinsic_changes_are_collected() {
 		let mut overlay = OverlayedChanges::default();
-		let _ = overlay.set_changes_trie_config(ChangesTrieConfig {
-			digest_interval: 4, digest_levels: 1,
-		});
+		overlay.set_collect_extrinsics(true);
 
 		overlay.set_storage(vec![100], Some(vec![101]));
 
diff --git a/primitives/state-machine/src/testing.rs b/primitives/state-machine/src/testing.rs
index 1baf6d6b4da70..39a34509b720b 100644
--- a/primitives/state-machine/src/testing.rs
+++ b/primitives/state-machine/src/testing.rs
@@ -17,12 +17,16 @@
 //! Test implementation for Externalities.
 
 use std::any::{Any, TypeId};
+use codec::Decode;
 use hash_db::Hasher;
 use crate::{
 	backend::Backend, OverlayedChanges, StorageTransactionCache, ext::Ext, InMemoryBackend,
+	StorageKey, StorageValue,
 	changes_trie::{
+		Configuration as ChangesTrieConfiguration,
 		InMemoryStorage as ChangesTrieInMemoryStorage,
 		BlockNumber as ChangesTrieBlockNumber,
+		State as ChangesTrieState,
 	},
 };
 use sp_core::{
@@ -45,6 +49,7 @@ where
 		<InMemoryBackend<H> as Backend<H>>::Transaction, H, N
 	>,
 	backend: InMemoryBackend<H>,
+	changes_trie_config: Option<ChangesTrieConfiguration>,
 	changes_trie_storage: ChangesTrieInMemoryStorage<H, N>,
 	extensions: Extensions,
 }
@@ -54,12 +59,19 @@ impl<H: Hasher, N: ChangesTrieBlockNumber> TestExternalities<H, N>
 		H::Out: Ord + 'static + codec::Codec
 {
 	/// Get externalities implementation.
-	pub fn ext(&mut self) -> Ext<H, N, InMemoryBackend<H>, ChangesTrieInMemoryStorage<H, N>> {
+	pub fn ext(&mut self) -> Ext<H, N, InMemoryBackend<H>> {
 		Ext::new(
 			&mut self.overlay,
 			&mut self.storage_transaction_cache,
 			&self.backend,
-			Some(&self.changes_trie_storage),
+			match self.changes_trie_config.clone() {
+				Some(config) => Some(ChangesTrieState {
+					config,
+					zero: 0.into(),
+					storage: &self.changes_trie_storage,
+				}),
+				None => None,
+			},
 			Some(&mut self.extensions),
 		)
 	}
@@ -72,21 +84,19 @@ impl<H: Hasher, N: ChangesTrieBlockNumber> TestExternalities<H, N>
 	/// Create a new instance of `TestExternalities` with code and storage.
 	pub fn new_with_code(code: &[u8], mut storage: Storage) -> Self {
 		let mut overlay = OverlayedChanges::default();
+		let changes_trie_config = storage.top.get(CHANGES_TRIE_CONFIG)
+			.and_then(|v| Decode::decode(&mut &v[..]).ok());
+		overlay.set_collect_extrinsics(changes_trie_config.is_some());
 
 		assert!(storage.top.keys().all(|key| !is_child_storage_key(key)));
 		assert!(storage.children.keys().all(|key| is_child_storage_key(key)));
 
-		super::set_changes_trie_config(
-			&mut overlay,
-			storage.top.get(&CHANGES_TRIE_CONFIG.to_vec()).cloned(),
-			false,
-		).expect("changes trie configuration is correct in test env; qed");
-
 		storage.top.insert(HEAP_PAGES.to_vec(), 8u64.encode());
 		storage.top.insert(CODE.to_vec(), code.to_vec());
 
 		TestExternalities {
 			overlay,
+			changes_trie_config,
 			changes_trie_storage: ChangesTrieInMemoryStorage::new(),
 			backend: storage.into(),
 			extensions: Default::default(),
@@ -95,7 +105,7 @@ impl<H: Hasher, N: ChangesTrieBlockNumber> TestExternalities<H, N>
 	}
 
 	/// Insert key/value into backend
-	pub fn insert(&mut self, k: Vec<u8>, v: Vec<u8>) {
+	pub fn insert(&mut self, k: StorageKey, v: StorageValue) {
 		self.backend = self.backend.update(vec![(None, vec![(k, Some(v))])]);
 	}
 
diff --git a/primitives/state-machine/src/trie_backend.rs b/primitives/state-machine/src/trie_backend.rs
index 1920ea40a88b5..dbaae323c09f2 100644
--- a/primitives/state-machine/src/trie_backend.rs
+++ b/primitives/state-machine/src/trie_backend.rs
@@ -20,10 +20,12 @@ use log::{warn, debug};
 use hash_db::Hasher;
 use sp_trie::{Trie, delta_trie_root, default_child_trie_root, child_delta_trie_root};
 use sp_trie::trie_types::{TrieDB, TrieError, Layout};
-use crate::trie_backend_essence::{TrieBackendEssence, TrieBackendStorage, Ephemeral};
-use crate::Backend;
 use sp_core::storage::ChildInfo;
 use codec::{Codec, Decode};
+use crate::{
+	StorageKey, StorageValue, Backend,
+	trie_backend_essence::{TrieBackendEssence, TrieBackendStorage, Ephemeral},
+};
 
 /// Patricia trie-based backend. Transaction type is an overlay of changes to commit.
 pub struct TrieBackend<S: TrieBackendStorage<H>, H: Hasher> {
@@ -72,7 +74,7 @@ impl<S: TrieBackendStorage<H>, H: Hasher> Backend<H> for TrieBackend<S, H> where
 	type Transaction = S::Overlay;
 	type TrieBackendStorage = S;
 
-	fn storage(&self, key: &[u8]) -> Result<Option<Vec<u8>>, Self::Error> {
+	fn storage(&self, key: &[u8]) -> Result<Option<StorageValue>, Self::Error> {
 		self.essence.storage(key)
 	}
 
@@ -81,11 +83,11 @@ impl<S: TrieBackendStorage<H>, H: Hasher> Backend<H> for TrieBackend<S, H> where
 		storage_key: &[u8],
 		child_info: ChildInfo,
 		key: &[u8],
-	) -> Result<Option<Vec<u8>>, Self::Error> {
+	) -> Result<Option<StorageValue>, Self::Error> {
 		self.essence.child_storage(storage_key, child_info, key)
 	}
 
-	fn next_storage_key(&self, key: &[u8]) -> Result<Option<Vec<u8>>, Self::Error> {
+	fn next_storage_key(&self, key: &[u8]) -> Result<Option<StorageKey>, Self::Error> {
 		self.essence.next_storage_key(key)
 	}
 
@@ -94,7 +96,7 @@ impl<S: TrieBackendStorage<H>, H: Hasher> Backend<H> for TrieBackend<S, H> where
 		storage_key: &[u8],
 		child_info: ChildInfo,
 		key: &[u8],
-	) -> Result<Option<Vec<u8>>, Self::Error> {
+	) -> Result<Option<StorageKey>, Self::Error> {
 		self.essence.next_child_storage_key(storage_key, child_info, key)
 	}
 
@@ -125,7 +127,7 @@ impl<S: TrieBackendStorage<H>, H: Hasher> Backend<H> for TrieBackend<S, H> where
 		self.essence.for_child_keys_with_prefix(storage_key, child_info, prefix, f)
 	}
 
-	fn pairs(&self) -> Vec<(Vec<u8>, Vec<u8>)> {
+	fn pairs(&self) -> Vec<(StorageKey, StorageValue)> {
 		let mut read_overlay = S::Overlay::default();
 		let eph = Ephemeral::new(self.essence.backend_storage(), &mut read_overlay);
 
@@ -149,7 +151,7 @@ impl<S: TrieBackendStorage<H>, H: Hasher> Backend<H> for TrieBackend<S, H> where
 		}
 	}
 
-	fn keys(&self, prefix: &[u8]) -> Vec<Vec<u8>> {
+	fn keys(&self, prefix: &[u8]) -> Vec<StorageKey> {
 		let mut read_overlay = S::Overlay::default();
 		let eph = Ephemeral::new(self.essence.backend_storage(), &mut read_overlay);
 
@@ -170,7 +172,7 @@ impl<S: TrieBackendStorage<H>, H: Hasher> Backend<H> for TrieBackend<S, H> where
 	}
 
 	fn storage_root<I>(&self, delta: I) -> (H::Out, S::Overlay)
-		where I: IntoIterator<Item=(Vec<u8>, Option<Vec<u8>>)>
+		where I: IntoIterator<Item=(StorageKey, Option<StorageValue>)>
 	{
 		let mut write_overlay = S::Overlay::default();
 		let mut root = *self.essence.root();
@@ -197,7 +199,7 @@ impl<S: TrieBackendStorage<H>, H: Hasher> Backend<H> for TrieBackend<S, H> where
 		delta: I,
 	) -> (H::Out, bool, Self::Transaction)
 	where
-		I: IntoIterator<Item=(Vec<u8>, Option<Vec<u8>>)>,
+		I: IntoIterator<Item=(StorageKey, Option<StorageValue>)>,
 		H::Out: Ord,
 	{
 		let default_root = default_child_trie_root::<Layout<H>>(storage_key);
diff --git a/primitives/state-machine/src/trie_backend_essence.rs b/primitives/state-machine/src/trie_backend_essence.rs
index f7f5006f41dab..2598682ae0668 100644
--- a/primitives/state-machine/src/trie_backend_essence.rs
+++ b/primitives/state-machine/src/trie_backend_essence.rs
@@ -25,7 +25,7 @@ use sp_trie::{Trie, MemoryDB, PrefixedMemoryDB, DBValue,
 	default_child_trie_root, read_trie_value, read_child_trie_value,
 	for_keys_in_child_trie, KeySpacedDB};
 use sp_trie::trie_types::{TrieDB, TrieError, Layout};
-use crate::backend::Consolidate;
+use crate::{backend::Consolidate, StorageKey, StorageValue};
 use sp_core::storage::ChildInfo;
 use codec::Encode;
 
@@ -67,7 +67,7 @@ impl<S: TrieBackendStorage<H>, H: Hasher> TrieBackendEssence<S, H> where H::Out:
 
 	/// Return the next key in the trie i.e. the minimum key that is strictly superior to `key` in
 	/// lexicographic order.
-	pub fn next_storage_key(&self, key: &[u8]) -> Result<Option<Vec<u8>>, String> {
+	pub fn next_storage_key(&self, key: &[u8]) -> Result<Option<StorageKey>, String> {
 		self.next_storage_key_from_root(&self.root, None, key)
 	}
 
@@ -78,7 +78,7 @@ impl<S: TrieBackendStorage<H>, H: Hasher> TrieBackendEssence<S, H> where H::Out:
 		storage_key: &[u8],
 		child_info: ChildInfo,
 		key: &[u8],
-	) -> Result<Option<Vec<u8>>, String> {
+	) -> Result<Option<StorageKey>, String> {
 		let child_root = match self.storage(storage_key)? {
 			Some(child_root) => child_root,
 			None => return Ok(None),
@@ -101,7 +101,7 @@ impl<S: TrieBackendStorage<H>, H: Hasher> TrieBackendEssence<S, H> where H::Out:
 		root: &H::Out,
 		child_info: Option<ChildInfo>,
 		key: &[u8],
-	) -> Result<Option<Vec<u8>>, String> {
+	) -> Result<Option<StorageKey>, String> {
 		let mut read_overlay = S::Overlay::default();
 		let eph = Ephemeral {
 			storage: &self.storage,
@@ -146,7 +146,7 @@ impl<S: TrieBackendStorage<H>, H: Hasher> TrieBackendEssence<S, H> where H::Out:
 	}
 
 	/// Get the value of storage at given key.
-	pub fn storage(&self, key: &[u8]) -> Result<Option<Vec<u8>>, String> {
+	pub fn storage(&self, key: &[u8]) -> Result<Option<StorageValue>, String> {
 		let mut read_overlay = S::Overlay::default();
 		let eph = Ephemeral {
 			storage: &self.storage,
@@ -164,7 +164,7 @@ impl<S: TrieBackendStorage<H>, H: Hasher> TrieBackendEssence<S, H> where H::Out:
 		storage_key: &[u8],
 		child_info: ChildInfo,
 		key: &[u8],
-	) -> Result<Option<Vec<u8>>, String> {
+	) -> Result<Option<StorageValue>, String> {
 		let root = self.storage(storage_key)?
 			.unwrap_or(default_child_trie_root::<Layout<H>>(storage_key).encode());
 
diff --git a/primitives/trie/Cargo.toml b/primitives/trie/Cargo.toml
index 78e32e33334df..a78a26db736c4 100644
--- a/primitives/trie/Cargo.toml
+++ b/primitives/trie/Cargo.toml
@@ -15,13 +15,13 @@ harness = false
 codec = { package = "parity-scale-codec", version = "1.0.0", default-features = false }
 sp-std = { version = "2.0.0", default-features = false, path = "../std" }
 hash-db = { version = "0.15.2", default-features = false }
-trie-db = { version = "0.18.1", default-features = false }
+trie-db = { version = "0.19.2", default-features = false }
 trie-root = { version = "0.15.2", default-features = false }
-memory-db = { version = "0.18.0", default-features = false }
+memory-db = { version = "0.18.1", default-features = false }
 sp-core = { version = "2.0.0", default-features = false, path = "../core" }
 
 [dev-dependencies]
-trie-bench = "0.18.0"
+trie-bench = "0.19.0"
 trie-standardmap = "0.15.2"
 criterion = "0.2.11"
 hex-literal = "0.2.1"
diff --git a/primitives/trie/src/lib.rs b/primitives/trie/src/lib.rs
index 4ca26542dd4bb..c71d3fb84ce79 100644
--- a/primitives/trie/src/lib.rs
+++ b/primitives/trie/src/lib.rs
@@ -27,6 +27,8 @@ use sp_std::boxed::Box;
 use sp_std::marker::PhantomData;
 use sp_std::vec::Vec;
 use hash_db::{Hasher, Prefix};
+use trie_db::proof::{generate_proof, verify_proof};
+pub use trie_db::proof::VerifyError;
 /// Our `NodeCodec`-specific error.
 pub use error::Error;
 /// The Substrate format implementation of `TrieStream`.
@@ -119,6 +121,47 @@ pub mod trie_types {
 	pub type TrieError<H> = trie_db::TrieError<H, super::Error>;
 }
 
+/// Create a proof for a subset of keys in a trie.
+///
+/// The `keys` may contain any set of keys regardless of each one of them is included
+/// in the `db`.
+///
+/// For a key `K` that is included in the `db` a proof of inclusion is generated.
+/// For a key `K` that is not included in the `db` a proof of non-inclusion is generated.
+/// These can be later checked in `verify_trie_proof`.
+pub fn generate_trie_proof<'a, L: TrieConfiguration, I, K, DB>(
+	db: &DB,
+	root: TrieHash<L>,
+	keys: I,
+) -> Result<Vec<Vec<u8>>, Box<TrieError<L>>> where
+	I: IntoIterator<Item=&'a K>,
+	K: 'a + AsRef<[u8]>,
+	DB: hash_db::HashDBRef<L::Hash, trie_db::DBValue>,
+{
+	let trie = TrieDB::<L>::new(db, &root)?;
+	generate_proof(&trie, keys)
+}
+
+/// Verify a set of key-value pairs against a trie root and a proof.
+///
+/// Checks a set of keys with optional values for inclusion in the proof that was generated by
+/// `generate_trie_proof`.
+/// If the value in the pair is supplied (`(key, Some(value))`), this key-value pair will be
+/// checked for inclusion in the proof.
+/// If the value is omitted (`(key, None)`), this key will be checked for non-inclusion in the
+/// proof.
+pub fn verify_trie_proof<'a, L: TrieConfiguration, I, K, V>(
+	root: &TrieHash<L>,
+	proof: &[Vec<u8>],
+	items: I,
+) -> Result<(), VerifyError<TrieHash<L>, error::Error>> where
+	I: IntoIterator<Item=&'a (K, Option<V>)>,
+	K: 'a + AsRef<[u8]>,
+	V: 'a + AsRef<[u8]>,
+{
+	verify_proof::<Layout<L::Hash>, _, _, _>(root, proof, items)
+}
+
 /// Determine a trie root given a hash DB and delta values.
 pub fn delta_trie_root<L: TrieConfiguration, I, A, B, DB>(
 	db: &mut DB,
@@ -727,4 +770,89 @@ mod tests {
 
 		assert_eq!(pairs, iter_pairs);
 	}
+
+	#[test]
+	fn proof_non_inclusion_works() {
+		let pairs = vec![
+			(hex!("0102").to_vec(), hex!("01").to_vec()),
+			(hex!("0203").to_vec(), hex!("0405").to_vec()),
+		];
+
+		let mut memdb = MemoryDB::default();
+		let mut root = Default::default();
+		populate_trie::<Layout>(&mut memdb, &mut root, &pairs);
+
+		let non_included_key: Vec<u8> = hex!("0909").to_vec();
+		let proof = generate_trie_proof::<Layout, _, _, _>(
+			&memdb,
+			root,
+			&[non_included_key.clone()]
+		).unwrap();
+
+		// Verifying that the K was not included into the trie should work.
+		assert!(verify_trie_proof::<Layout, _, _, Vec<u8>>(
+				&root,
+				&proof,
+				&[(non_included_key.clone(), None)],
+			).is_ok()
+		);
+
+		// Verifying that the K was included into the trie should fail.
+		assert!(verify_trie_proof::<Layout, _, _, Vec<u8>>(
+				&root,
+				&proof,
+				&[(non_included_key, Some(hex!("1010").to_vec()))],
+			).is_err()
+		);
+	}
+
+	#[test]
+	fn proof_inclusion_works() {
+		let pairs = vec![
+			(hex!("0102").to_vec(), hex!("01").to_vec()),
+			(hex!("0203").to_vec(), hex!("0405").to_vec()),
+		];
+
+		let mut memdb = MemoryDB::default();
+		let mut root = Default::default();
+		populate_trie::<Layout>(&mut memdb, &mut root, &pairs);
+
+		let proof = generate_trie_proof::<Layout, _, _, _>(
+			&memdb,
+			root,
+			&[pairs[0].0.clone()]
+		).unwrap();
+
+		// Check that a K, V included into the proof are verified.
+		assert!(verify_trie_proof::<Layout, _, _, _>(
+				&root,
+				&proof,
+				&[(pairs[0].0.clone(), Some(pairs[0].1.clone()))]
+			).is_ok()
+		);
+
+		// Absence of the V is not verified with the proof that has K, V included.
+		assert!(verify_trie_proof::<Layout, _, _, Vec<u8>>(
+				&root,
+				&proof,
+				&[(pairs[0].0.clone(), None)]
+			).is_err()
+		);
+
+		// K not included into the trie is not verified.
+		assert!(verify_trie_proof::<Layout, _, _, _>(
+				&root,
+				&proof,
+				&[(hex!("4242").to_vec(), Some(pairs[0].1.clone()))]
+			).is_err()
+		);
+
+		// K included into the trie but not included into the proof is not verified.
+		assert!(verify_trie_proof::<Layout, _, _, _>(
+				&root,
+				&proof,
+				&[(pairs[1].0.clone(), Some(pairs[1].1.clone()))]
+			).is_err()
+		);
+	}
 }
diff --git a/primitives/version/Cargo.toml b/primitives/version/Cargo.toml
index fbbf0cfa94607..784051b56e5e1 100644
--- a/primitives/version/Cargo.toml
+++ b/primitives/version/Cargo.toml
@@ -7,7 +7,7 @@ edition = "2018"
 [dependencies]
 impl-serde = { version = "0.2.3", optional = true }
 serde = { version = "1.0.101", optional = true, features = ["derive"] }
-codec = { package = "parity-scale-codec", version = "1.0.5", default-features = false, features = ["derive"] }
+codec = { package = "parity-scale-codec", version = "1.1.2", default-features = false, features = ["derive"] }
 sp-std = { version = "2.0.0", default-features = false, path = "../std" }
 sp-runtime = { version = "2.0.0", default-features = false, path = "../runtime" }
 
diff --git a/primitives/version/src/lib.rs b/primitives/version/src/lib.rs
index 3211c46253631..0534f87490868 100644
--- a/primitives/version/src/lib.rs
+++ b/primitives/version/src/lib.rs
@@ -25,11 +25,11 @@ use std::fmt;
 #[cfg(feature = "std")]
 use std::collections::HashSet;
 
-use codec::Encode;
-#[cfg(feature = "std")]
-use codec::Decode;
+use codec::{Encode, Decode};
 use sp_runtime::RuntimeString;
 pub use sp_runtime::create_runtime_str;
+#[doc(hidden)]
+pub use sp_std;
 
 #[cfg(feature = "std")]
 use sp_runtime::{traits::Block as BlockT, generic::BlockId};
@@ -37,25 +37,13 @@ use sp_runtime::{traits::Block as BlockT, generic::BlockId};
 /// The identity of a particular API interface that the runtime might provide.
 pub type ApiId = [u8; 8];
 
-/// A vector of pairs of `ApiId` and a `u32` for version. For `"std"` builds, this
-/// is a `Cow`.
-#[cfg(feature = "std")]
-pub type ApisVec = std::borrow::Cow<'static, [(ApiId, u32)]>;
-/// A vector of pairs of `ApiId` and a `u32` for version. For `"no-std"` builds, this
-/// is just a reference.
-#[cfg(not(feature = "std"))]
-pub type ApisVec = &'static [(ApiId, u32)];
+/// A vector of pairs of `ApiId` and a `u32` for version.
+pub type ApisVec = sp_std::borrow::Cow<'static, [(ApiId, u32)]>;
 
 /// Create a vector of Api declarations.
 #[macro_export]
-#[cfg(feature = "std")]
-macro_rules! create_apis_vec {
-	( $y:expr ) => { std::borrow::Cow::Borrowed(& $y) }
-}
-#[macro_export]
-#[cfg(not(feature = "std"))]
 macro_rules! create_apis_vec {
-	( $y:expr ) => { & $y }
+	( $y:expr ) => { $crate::sp_std::borrow::Cow::Borrowed(& $y) }
 }
 
 /// Runtime version.
@@ -63,8 +51,8 @@ macro_rules! create_apis_vec {
 /// This triplet have different semantics and mis-interpretation could cause problems.
 /// In particular: bug fixes should result in an increment of `spec_version` and possibly `authoring_version`,
 /// absolutely not `impl_version` since they change the semantics of the runtime.
-#[derive(Clone, PartialEq, Eq, Encode, Default, sp_runtime::RuntimeDebug)]
-#[cfg_attr(feature = "std", derive(Serialize, Deserialize, Decode))]
+#[derive(Clone, PartialEq, Eq, Encode, Decode, Default, sp_runtime::RuntimeDebug)]
+#[cfg_attr(feature = "std", derive(Serialize, Deserialize))]
 #[cfg_attr(feature = "std", serde(rename_all = "camelCase"))]
 pub struct RuntimeVersion {
 	/// Identifies the different Substrate runtimes. There'll be at least polkadot and node.
diff --git a/primitives/wasm-interface/src/lib.rs b/primitives/wasm-interface/src/lib.rs
index bc34bfda9700b..b0bbbf82db3c1 100644
--- a/primitives/wasm-interface/src/lib.rs
+++ b/primitives/wasm-interface/src/lib.rs
@@ -39,13 +39,17 @@ pub enum ValueType {
 /// Values supported by Substrate on the boundary between host/Wasm.
 #[derive(PartialEq, Debug, Clone, Copy)]
 pub enum Value {
-	/// An `i32` value.
+	/// A 32-bit integer.
 	I32(i32),
-	/// An `i64` value.
+	/// A 64-bit integer.
 	I64(i64),
-	/// An nan-preserving `f32` value.
+	/// A 32-bit floating-point number stored as raw bit pattern.
+	///
+	/// You can materialize this value using `f32::from_bits`.
 	F32(u32),
-	/// An nan-preserving `f64` value.
+	/// A 64-bit floating-point number stored as raw bit pattern.
+	///
+	/// You can materialize this value using `f64::from_bits`.
 	F64(u64),
 }
 
diff --git a/test-utils/client/Cargo.toml b/test-utils/client/Cargo.toml
index 05dc41b2233a1..8b1ebc39f4724 100644
--- a/test-utils/client/Cargo.toml
+++ b/test-utils/client/Cargo.toml
@@ -6,10 +6,10 @@ edition = "2018"
 
 [dependencies]
 sc-client-api = { version = "2.0.0", path = "../../client/api" }
-sc-client = { version = "2.0.0", path = "../../client/" }
-sc-client-db = { version = "2.0.0", features = ["test-helpers"], path = "../../client/db" }
+sc-client = { version = "0.8", path = "../../client/" }
+sc-client-db = { version = "0.8", features = ["test-helpers"], path = "../../client/db" }
 sp-consensus = { version = "0.8", path = "../../primitives/consensus/common" }
-sc-executor = { version = "2.0.0", path = "../../client/executor" }
+sc-executor = { version = "0.8", path = "../../client/executor" }
 futures = "0.3.1"
 hash-db = "0.15.2"
 sp-keyring = { version = "2.0.0", path = "../../primitives/keyring" }
@@ -17,4 +17,4 @@ codec = { package = "parity-scale-codec", version = "1.0.0" }
 sp-core = { version = "2.0.0", path = "../../primitives/core" }
 sp-runtime = { version = "2.0.0", path = "../../primitives/runtime" }
 sp-blockchain = { version = "2.0.0", path = "../../primitives/blockchain" }
-sp-state-machine = { version = "2.0.0", path = "../../primitives/state-machine" }
+sp-state-machine = { version = "0.8", path = "../../primitives/state-machine" }
diff --git a/test-utils/client/src/client_ext.rs b/test-utils/client/src/client_ext.rs
index 67d08c5fa600f..aa7383e3ab367 100644
--- a/test-utils/client/src/client_ext.rs
+++ b/test-utils/client/src/client_ext.rs
@@ -64,7 +64,7 @@ pub trait ClientBlockImportExt<Block: BlockT>: Sized {
 impl<B, E, RA, Block> ClientExt<Block> for Client<B, E, Block, RA>
 	where
 		B: sc_client_api::backend::Backend<Block>,
-		E: sc_client::CallExecutor<Block>,
+		E: sc_client::CallExecutor<Block> + 'static,
 		Self: BlockImport<Block, Error = ConsensusError>,
 		Block: BlockT,
 {
diff --git a/test-utils/client/src/lib.rs b/test-utils/client/src/lib.rs
index ac1cfe4d6b6a5..8603b26d50a58 100644
--- a/test-utils/client/src/lib.rs
+++ b/test-utils/client/src/lib.rs
@@ -165,7 +165,7 @@ impl<Executor, Backend, G: GenesisInit> TestClientBuilder<Executor, Backend, G>
 		>,
 		sc_client::LongestChain<Backend, Block>,
 	) where
-		Executor: sc_client::CallExecutor<Block>,
+		Executor: sc_client::CallExecutor<Block> + 'static,
 		Backend: sc_client_api::backend::Backend<Block>,
 		Block: BlockT,
 	{
@@ -190,7 +190,7 @@ impl<Executor, Backend, G: GenesisInit> TestClientBuilder<Executor, Backend, G>
 		let client = sc_client::Client::new(
 			self.backend.clone(),
 			executor,
-			storage,
+			&storage,
 			Default::default(),
 			Default::default(),
 			ExecutionExtensions::new(
@@ -224,8 +224,8 @@ impl<E, Backend, G: GenesisInit> TestClientBuilder<
 		sc_client::LongestChain<Backend, Block>,
 	) where
 		I: Into<Option<NativeExecutor<E>>>,
-		E: sc_executor::NativeExecutionDispatch,
-		Backend: sc_client_api::backend::Backend<Block>,
+		E: sc_executor::NativeExecutionDispatch + 'static,
+		Backend: sc_client_api::backend::Backend<Block> + 'static,
 		Block: BlockT,
 	{
 		let executor = executor.into().unwrap_or_else(||
diff --git a/test-utils/runtime/Cargo.toml b/test-utils/runtime/Cargo.toml
index 6444c7fcf1463..b827163a1b0f7 100644
--- a/test-utils/runtime/Cargo.toml
+++ b/test-utils/runtime/Cargo.toml
@@ -32,15 +32,15 @@ pallet-babe = { version = "2.0.0", default-features = false, path = "../../frame
 frame-system = { version = "2.0.0", default-features = false, path = "../../frame/system" }
 frame-system-rpc-runtime-api = { version = "2.0.0", default-features = false, path = "../../frame/system/rpc/runtime-api" }
 pallet-timestamp = { version = "2.0.0", default-features = false, path = "../../frame/timestamp" }
-sc-client = { version = "2.0.0", optional = true, path = "../../client" }
+sc-client = { version = "0.8", optional = true, path = "../../client" }
 sp-trie = { version = "2.0.0", default-features = false, path = "../../primitives/trie" }
 sp-transaction-pool = { version = "2.0.0", default-features = false, path = "../../primitives/transaction-pool" }
-trie-db = { version = "0.18.1", default-features = false }
+trie-db = { version = "0.19.2", default-features = false }
 
 [dev-dependencies]
-sc-executor = { version = "2.0.0", path = "../../client/executor" }
+sc-executor = { version = "0.8", path = "../../client/executor" }
 substrate-test-runtime-client = { version = "2.0.0", path = "./client" }
-sp-state-machine = { version = "2.0.0", path = "../../primitives/state-machine" }
+sp-state-machine = { version = "0.8", path = "../../primitives/state-machine" }
 
 [build-dependencies]
 wasm-builder-runner = { version = "1.0.4", package = "substrate-wasm-builder-runner", path = "../../utils/wasm-builder-runner" }
diff --git a/test-utils/runtime/client/Cargo.toml b/test-utils/runtime/client/Cargo.toml
index 8e08f6a1b5ec8..aa33f550127e8 100644
--- a/test-utils/runtime/client/Cargo.toml
+++ b/test-utils/runtime/client/Cargo.toml
@@ -5,7 +5,7 @@ authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2018"
 
 [dependencies]
-sc-block-builder = { version = "2.0.0", path = "../../../client/block-builder" }
+sc-block-builder = { version = "0.8", path = "../../../client/block-builder" }
 substrate-test-client = { version = "2.0.0", path = "../../client" }
 sp-core = { version = "2.0.0", path = "../../../primitives/core" }
 substrate-test-runtime = { version = "2.0.0", path = "../../runtime" }
@@ -14,5 +14,5 @@ sp-api = { version = "2.0.0", path = "../../../primitives/api" }
 sp-blockchain = { version = "2.0.0", path = "../../../primitives/blockchain" }
 codec = { package = "parity-scale-codec", version = "1.0.0" }
 sc-client-api = { version = "2.0.0", path = "../../../client/api" }
-sc-client = { version = "2.0.0", path = "../../../client/" }
+sc-client = { version = "0.8", path = "../../../client/" }
 futures = "0.3.1"
diff --git a/test-utils/runtime/client/src/block_builder_ext.rs b/test-utils/runtime/client/src/block_builder_ext.rs
index 7626ac2ffa5f4..6b9a6f79ab191 100644
--- a/test-utils/runtime/client/src/block_builder_ext.rs
+++ b/test-utils/runtime/client/src/block_builder_ext.rs
@@ -17,6 +17,7 @@
 //! Block Builder extensions for tests.
 
 use sp_api::{ApiExt, ProvideRuntimeApi};
+use sp_core::ChangesTrieConfiguration;
 use sc_client_api::backend;
 use sp_runtime::traits::HasherFor;
 
@@ -32,6 +33,11 @@ pub trait BlockBuilderExt {
 		key: Vec<u8>,
 		value: Option<Vec<u8>>,
 	) -> Result<(), sp_blockchain::Error>;
+	/// Add changes trie configuration update extrinsic to the block.
+	fn push_changes_trie_configuration_update(
+		&mut self,
+		new_config: Option<ChangesTrieConfiguration>,
+	) -> Result<(), sp_blockchain::Error>;
 }
 
 impl<'a, A, B> BlockBuilderExt for sc_block_builder::BlockBuilder<'a, substrate_test_runtime::Block, A, B> where
@@ -57,4 +63,11 @@ impl<'a, A, B> BlockBuilderExt for sc_block_builder::BlockBuilder<'a, substrate_
 	) -> Result<(), sp_blockchain::Error> {
 		self.push(substrate_test_runtime::Extrinsic::StorageChange(key, value))
 	}
+
+	fn push_changes_trie_configuration_update(
+		&mut self,
+		new_config: Option<ChangesTrieConfiguration>,
+	) -> Result<(), sp_blockchain::Error> {
+		self.push(substrate_test_runtime::Extrinsic::ChangesTrieConfigUpdate(new_config))
+	}
 }
diff --git a/test-utils/runtime/client/src/lib.rs b/test-utils/runtime/client/src/lib.rs
index 4faf7f8ab4851..7646f4a96023c 100644
--- a/test-utils/runtime/client/src/lib.rs
+++ b/test-utils/runtime/client/src/lib.rs
@@ -30,7 +30,7 @@ pub use sc_client::LongestChain;
 
 pub use self::block_builder_ext::BlockBuilderExt;
 
-use sp_core::sr25519;
+use sp_core::{sr25519, ChangesTrieConfiguration};
 use sp_core::storage::{ChildInfo, Storage, StorageChild};
 use substrate_test_runtime::genesismap::{GenesisConfig, additional_storage_with_genesis};
 use sp_runtime::traits::{Block as BlockT, Header as HeaderT, Hash as HashT, NumberFor, HasherFor};
@@ -42,7 +42,6 @@ use sc_client::{
 	},
 };
 
-
 /// A prelude to import in tests.
 pub mod prelude {
 	// Trait extensions
@@ -59,21 +58,12 @@ pub mod prelude {
 	pub use super::{AccountKeyring, Sr25519Keyring};
 }
 
-mod local_executor {
-	#![allow(missing_docs)]
-	use substrate_test_runtime;
-	use crate::sc_executor::native_executor_instance;
-	// FIXME #1576 change the macro and pass in the `BlakeHasher` that dispatch needs from here instead
-	native_executor_instance!(
-		pub LocalExecutor,
-		substrate_test_runtime::api::dispatch,
-		substrate_test_runtime::native_version
-	);
+sc_executor::native_executor_instance! {
+	pub LocalExecutor,
+	substrate_test_runtime::api::dispatch,
+	substrate_test_runtime::native_version,
 }
 
-/// Native executor used for tests.
-pub use self::local_executor::LocalExecutor;
-
 /// Test client database backend.
 pub type Backend = substrate_test_client::Backend<substrate_test_runtime::Block>;
 
@@ -101,7 +91,7 @@ pub type LightExecutor = sc_client::light::call_executor::GenesisCallExecutor<
 /// Parameters of test-client builder with test-runtime.
 #[derive(Default)]
 pub struct GenesisParameters {
-	support_changes_trie: bool,
+	changes_trie_config: Option<ChangesTrieConfiguration>,
 	heap_pages_override: Option<u64>,
 	extra_storage: Storage,
 }
@@ -109,7 +99,7 @@ pub struct GenesisParameters {
 impl GenesisParameters {
 	fn genesis_config(&self) -> GenesisConfig {
 		GenesisConfig::new(
-			self.support_changes_trie,
+			self.changes_trie_config.clone(),
 			vec![
 				sr25519::Public::from(Sr25519Keyring::Alice).into(),
 				sr25519::Public::from(Sr25519Keyring::Bob).into(),
@@ -180,9 +170,9 @@ pub trait TestClientBuilderExt<B>: Sized {
 	/// Returns a mutable reference to the genesis parameters.
 	fn genesis_init_mut(&mut self) -> &mut GenesisParameters;
 
-	/// Enable or disable support for changes trie in genesis.
-	fn set_support_changes_trie(mut self, support_changes_trie: bool) -> Self {
-		self.genesis_init_mut().support_changes_trie = support_changes_trie;
+	/// Set changes trie configuration for genesis.
+	fn changes_trie_config(mut self, config: Option<ChangesTrieConfiguration>) -> Self {
+		self.genesis_init_mut().changes_trie_config = config;
 		self
 	}
 
@@ -245,7 +235,7 @@ impl<B> TestClientBuilderExt<B> for TestClientBuilder<
 	sc_client::LocalCallExecutor<B, sc_executor::NativeExecutor<LocalExecutor>>,
 	B
 > where
-	B: sc_client_api::backend::Backend<substrate_test_runtime::Block>,
+	B: sc_client_api::backend::Backend<substrate_test_runtime::Block> + 'static,
 	// Rust bug: https://github.com/rust-lang/rust/issues/24159
 	<B as sc_client_api::backend::Backend<substrate_test_runtime::Block>>::State:
 		sp_api::StateBackend<HasherFor<substrate_test_runtime::Block>>,
@@ -353,7 +343,7 @@ pub fn new_light() -> (
 	let storage = sc_client_db::light::LightStorage::new_test();
 	let blockchain = Arc::new(sc_client::light::blockchain::Blockchain::new(storage));
 	let backend = Arc::new(LightBackend::new(blockchain.clone()));
-	let executor = NativeExecutor::new(WasmExecutionMethod::Interpreted, None);
+	let executor = new_native_executor();
 	let local_call_executor = sc_client::LocalCallExecutor::new(backend.clone(), executor);
 	let call_executor = LightExecutor::new(
 		backend.clone(),
@@ -372,3 +362,8 @@ pub fn new_light() -> (
 pub fn new_light_fetcher() -> LightFetcher {
 	LightFetcher::default()
 }
+
+/// Create a new native executor.
+pub fn new_native_executor() -> sc_executor::NativeExecutor<LocalExecutor> {
+	sc_executor::NativeExecutor::new(sc_executor::WasmExecutionMethod::Interpreted, None)
+}
diff --git a/test-utils/runtime/src/genesismap.rs b/test-utils/runtime/src/genesismap.rs
index f6fbcddf44e16..25d9a807ccee1 100644
--- a/test-utils/runtime/src/genesismap.rs
+++ b/test-utils/runtime/src/genesismap.rs
@@ -36,7 +36,7 @@ pub struct GenesisConfig {
 
 impl GenesisConfig {
 	pub fn new(
-		support_changes_trie: bool,
+		changes_trie_config: Option<ChangesTrieConfiguration>,
 		authorities: Vec<AuthorityId>,
 		endowed_accounts: Vec<AccountId>,
 		balance: u64,
@@ -44,10 +44,7 @@ impl GenesisConfig {
 		extra_storage: Storage,
 	) -> Self {
 		GenesisConfig {
-			changes_trie_config: match support_changes_trie {
-				true => Some(super::changes_trie_config()),
-				false => None,
-			},
+			changes_trie_config,
 			authorities: authorities.clone(),
 			balances: endowed_accounts.into_iter().map(|a| (a, balance)).collect(),
 			heap_pages_override,
diff --git a/test-utils/runtime/src/lib.rs b/test-utils/runtime/src/lib.rs
index 4dfddfda21aec..e68ed5f6fc17e 100644
--- a/test-utils/runtime/src/lib.rs
+++ b/test-utils/runtime/src/lib.rs
@@ -25,7 +25,7 @@ pub mod system;
 use sp_std::{prelude::*, marker::PhantomData};
 use codec::{Encode, Decode, Input, Error};
 
-use sp_core::{Blake2Hasher, OpaqueMetadata, RuntimeDebug};
+use sp_core::{Blake2Hasher, OpaqueMetadata, RuntimeDebug, ChangesTrieConfiguration};
 use sp_application_crypto::{ed25519, sr25519, RuntimeAppPublic};
 use trie_db::{TrieMut, Trie};
 use sp_trie::PrefixedMemoryDB;
@@ -65,7 +65,10 @@ pub const VERSION: RuntimeVersion = RuntimeVersion {
 	impl_name: create_runtime_str!("parity-test"),
 	authoring_version: 1,
 	spec_version: 1,
+	#[cfg(feature = "std")]
 	impl_version: 1,
+	#[cfg(not(feature = "std"))]
+	impl_version: 2,
 	apis: RUNTIME_API_VERSIONS,
 };
 
@@ -108,6 +111,7 @@ pub enum Extrinsic {
 	Transfer(Transfer, AccountSignature),
 	IncludeData(Vec<u8>),
 	StorageChange(Vec<u8>, Option<Vec<u8>>),
+	ChangesTrieConfigUpdate(Option<ChangesTrieConfiguration>),
 }
 
 #[cfg(feature = "std")]
@@ -132,6 +136,8 @@ impl BlindCheckable for Extrinsic {
 			},
 			Extrinsic::IncludeData(_) => Err(InvalidTransaction::BadProof.into()),
 			Extrinsic::StorageChange(key, value) => Ok(Extrinsic::StorageChange(key, value)),
+			Extrinsic::ChangesTrieConfigUpdate(new_config) =>
+				Ok(Extrinsic::ChangesTrieConfigUpdate(new_config)),
 		}
 	}
 }
@@ -193,14 +199,6 @@ pub fn run_tests(mut input: &[u8]) -> Vec<u8> {
 	[stxs.len() as u8].encode()
 }
 
-/// Changes trie configuration (optionally) used in tests.
-pub fn changes_trie_config() -> sp_core::ChangesTrieConfiguration {
-	sp_core::ChangesTrieConfiguration {
-		digest_interval: 4,
-		digest_levels: 2,
-	}
-}
-
 /// A type that can not be decoded.
 #[derive(PartialEq)]
 pub struct DecodeFails<B: BlockT> {
diff --git a/test-utils/runtime/src/system.rs b/test-utils/runtime/src/system.rs
index b04ebc1cf2f56..4d12ab8437d5b 100644
--- a/test-utils/runtime/src/system.rs
+++ b/test-utils/runtime/src/system.rs
@@ -35,7 +35,7 @@ use frame_system::Trait;
 use crate::{
 	AccountId, BlockNumber, Extrinsic, Transfer, H256 as Hash, Block, Header, Digest, AuthorityId
 };
-use sp_core::storage::well_known_keys;
+use sp_core::{storage::well_known_keys, ChangesTrieConfiguration};
 
 const NONCE_OF: &[u8] = b"nonce:";
 const BALANCE_OF: &[u8] = b"balance:";
@@ -51,6 +51,7 @@ decl_storage! {
 		Number get(fn number): Option<BlockNumber>;
 		ParentHash get(fn parent_hash): Hash;
 		NewAuthorities get(fn new_authorities): Option<Vec<AuthorityId>>;
+		NewChangesTrieConfig get(fn new_changes_trie_config): Option<Option<ChangesTrieConfiguration>>;
 		StorageDigest get(fn storage_digest): Option<Digest>;
 		Authorities get(fn authorities) config(): Vec<AuthorityId>;
 	}
@@ -206,6 +207,8 @@ pub fn finalize_block() -> Header {
 	let mut digest = <StorageDigest>::take().expect("StorageDigest is set by `initialize_block`");
 
 	let o_new_authorities = <NewAuthorities>::take();
+	let new_changes_trie_config = <NewChangesTrieConfig>::take();
+
 	// This MUST come after all changes to storage are done. Otherwise we will fail the
 	// “Storage root does not match that calculated” assertion.
 	let storage_root = Hash::decode(&mut &storage_root()[..])
@@ -222,6 +225,12 @@ pub fn finalize_block() -> Header {
 		digest.push(generic::DigestItem::Consensus(*b"babe", new_authorities.encode()));
 	}
 
+	if let Some(new_config) = new_changes_trie_config {
+		digest.push(generic::DigestItem::ChangesTrieSignal(
+			generic::ChangesTrieSignal::NewConfiguration(new_config)
+		));
+	}
+
 	Header {
 		number,
 		extrinsics_root,
@@ -244,6 +253,8 @@ fn execute_transaction_backend(utx: &Extrinsic) -> ApplyExtrinsicResult {
 		Extrinsic::AuthoritiesChange(ref new_auth) => execute_new_authorities_backend(new_auth),
 		Extrinsic::IncludeData(_) => Ok(Ok(())),
 		Extrinsic::StorageChange(key, value) => execute_storage_change(key, value.as_ref().map(|v| &**v)),
+		Extrinsic::ChangesTrieConfigUpdate(ref new_config) =>
+			execute_changes_trie_config_update(new_config.clone()),
 	}
 }
 
@@ -286,6 +297,18 @@ fn execute_storage_change(key: &[u8], value: Option<&[u8]>) -> ApplyExtrinsicRes
 	Ok(Ok(()))
 }
 
+fn execute_changes_trie_config_update(new_config: Option<ChangesTrieConfiguration>) -> ApplyExtrinsicResult {
+	match new_config.clone() {
+		Some(new_config) => storage::unhashed::put_raw(
+			well_known_keys::CHANGES_TRIE_CONFIG,
+			&new_config.encode(),
+		),
+		None => storage::unhashed::kill(well_known_keys::CHANGES_TRIE_CONFIG),
+	}
+	<NewChangesTrieConfig>::put(new_config);
+	Ok(Ok(()))
+}
+
 #[cfg(feature = "std")]
 fn info_expect_equal_hash(given: &Hash, expected: &Hash) {
 	use sp_core::hexdisplay::HexDisplay;
diff --git a/utils/browser/Cargo.toml b/utils/browser/Cargo.toml
index b58774075b34b..cfceaa143c7be 100644
--- a/utils/browser/Cargo.toml
+++ b/utils/browser/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "browser-utils"
-version = "2.0.0"
+version = "0.8.0"
 authors = ["Parity Technologies <admin@parity.io>"]
 description = "Utilities for creating a browser light-client."
 edition = "2018"
@@ -16,7 +16,7 @@ js-sys = "0.3.34"
 wasm-bindgen = "0.2.57"
 wasm-bindgen-futures = "0.4.7"
 kvdb-web = "0.3"
-service = { version = "2.0.0", package = "sc-service", path = "../../client/service", default-features = false }
+service = { version = "0.8", package = "sc-service", path = "../../client/service", default-features = false }
 network = { package = "sc-network", path = "../../client/network" }
 chain-spec = { package = "sc-chain-spec", path = "../../client/chain-spec" }
 
diff --git a/utils/browser/src/lib.rs b/utils/browser/src/lib.rs
index e404c6612906c..0dbde57182766 100644
--- a/utils/browser/src/lib.rs
+++ b/utils/browser/src/lib.rs
@@ -22,10 +22,7 @@ use service::{
 	ChainSpec, RuntimeGenesis
 };
 use wasm_bindgen::prelude::*;
-use futures::{
-	TryFutureExt as _, FutureExt as _, Stream as _, Future as _, TryStreamExt as _,
-	channel::{oneshot, mpsc}, future::{poll_fn, ok}, compat::*,
-};
+use futures::{prelude::*, channel::{oneshot, mpsc}, future::{poll_fn, ok}, compat::*};
 use std::task::Poll;
 use std::pin::Pin;
 use chain_spec::Extension;
@@ -82,8 +79,7 @@ struct RpcMessage {
 }
 
 /// Create a Client object that connects to a service.
-pub fn start_client(service: impl AbstractService) -> Client {
-	let mut service = service.compat();
+pub fn start_client(mut service: impl AbstractService) -> Client {
 	// We dispatch a background task responsible for processing the service.
 	//
 	// The main action performed by the code below consists in polling the service with
@@ -94,10 +90,8 @@ pub fn start_client(service: impl AbstractService) -> Client {
 		loop {
 			match Pin::new(&mut rpc_send_rx).poll_next(cx) {
 				Poll::Ready(Some(message)) => {
-					let fut = service.get_ref()
+					let fut = service
 						.rpc_query(&message.session, &message.rpc_json)
-						.compat()
-						.unwrap_or_else(|_| None)
 						.boxed();
 					let _ = message.send_back.send(fut);
 				},
diff --git a/utils/frame/rpc/support/Cargo.toml b/utils/frame/rpc/support/Cargo.toml
index f26a69cc5fa0c..19451743cd268 100644
--- a/utils/frame/rpc/support/Cargo.toml
+++ b/utils/frame/rpc/support/Cargo.toml
@@ -12,7 +12,7 @@ codec = { package = "parity-scale-codec", version = "1" }
 serde = "1"
 frame-support = { version = "2.0.0", path = "../../../../frame/support" }
 sp-storage = { version = "2.0.0", path = "../../../../primitives/storage" }
-sc-rpc-api = { version = "2.0.0", path = "../../../../client/rpc-api" }
+sc-rpc-api = { version = "0.8", path = "../../../../client/rpc-api" }
 
 [dev-dependencies]
 frame-system = { version = "2.0.0", path = "../../../../frame/system" }
diff --git a/utils/frame/rpc/system/Cargo.toml b/utils/frame/rpc/system/Cargo.toml
index 1a479c54e57d5..39f7735eed682 100644
--- a/utils/frame/rpc/system/Cargo.toml
+++ b/utils/frame/rpc/system/Cargo.toml
@@ -5,7 +5,7 @@ authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2018"
 
 [dependencies]
-sc-client = { version = "2.0.0", path = "../../../../client/" }
+sc-client = { version = "0.8", path = "../../../../client/" }
 codec = { package = "parity-scale-codec", version = "1.0.0" }
 futures = "0.3.1"
 jsonrpc-core = "14.0.3"
diff --git a/utils/grafana-data-source/src/database.rs b/utils/grafana-data-source/src/database.rs
deleted file mode 100644
index f20917cf785d4..0000000000000
--- a/utils/grafana-data-source/src/database.rs
+++ /dev/null
@@ -1,154 +0,0 @@
-// Copyright 2019-2020 Parity Technologies (UK) Ltd.
-// This file is part of Substrate.
-
-// Substrate is free software: you can redistribute it and/or modify
-// it under the terms of the GNU General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-
-// Substrate is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU General Public License for more details.
-
-// You should have received a copy of the GNU General Public License
-// along with Substrate.  If not, see <http://www.gnu.org/licenses/>.
-
-use std::collections::HashMap;
-use std::convert::TryFrom;
-use crate::Error;
-
-pub struct Database {
-	base_timestamp: i64,
-	storage: HashMap<String, Vec<Datapoint>>
-}
-
-impl Database {
-	/// Create a new Database.
-	pub fn new() -> Self {
-		Self {
-			base_timestamp: now_millis(),
-			storage: HashMap::new()
-		}
-	}
-
-	/// Produce an iterator for keys starting with a base string.
-	pub fn keys_starting_with<'a>(&'a self, base: &'a str) -> impl Iterator<Item = String> + 'a {
-		self.storage.keys()
-			.filter(move |key| key.starts_with(base))
-			.cloned()
-	}
-
-	/// Select `max_datapoints` datapoints that have been added between `from` and `to`.
-	pub fn datapoints_between(&self, key: &str, from: i64, to: i64, max_datapoints: usize) -> Option<Vec<(f32, i64)>> {
-		self.storage.get(key)
-			.map(|vec| {
-				let from = find_index(vec, self.base_timestamp, from);
-				let to = find_index(vec, self.base_timestamp, to);
-				let slice = &vec[from .. to];
-
-				if max_datapoints == 0 {
-					Vec::new()
-				} else if max_datapoints >= slice.len() {
-					// Just convert the slice as-is
-					slice.iter()
-						.map(|dp| dp.make_absolute(self.base_timestamp))
-						.collect()
-				} else {
-					// We have more datapoints than we need, so we need to skip some
-					(0 .. max_datapoints - 1)
-						.map(|i| &slice[i * slice.len() / (max_datapoints - 1)])
-						.chain(slice.last())
-						.map(|dp| dp.make_absolute(self.base_timestamp))
-						.collect()
-				}
-			})
-	}
-
-	/// Push a new datapoint. Will error if the base timestamp hasn't been updated in `2^32`
-	/// milliseconds (49 days).
-	pub fn push(&mut self, key: &str, value: f32) -> Result<(), Error> {
-		self.storage.entry(key.into())
-			.or_insert_with(Vec::new)
-			.push(Datapoint::new(self.base_timestamp, value)?);
-
-		Ok(())
-	}
-
-	/// Set a new base timestamp, and remove metrics older than this new timestamp. Errors if the
-	/// difference between timestamps is greater than `2^32` milliseconds (49 days).
-	pub fn truncate(&mut self, new_base_timestamp: i64) -> Result<(), Error> {
-		// Ensure that the new base is older.
-		if self.base_timestamp >= new_base_timestamp {
-			return Ok(());
-		}
-
-		// If the old base timestamp was too long ago, the
-		let delta = u32::try_from(new_base_timestamp - self.base_timestamp)
-			.map_err(Error::Timestamp)?;
-
-		for metric in self.storage.values_mut() {
-			// Find the index of the oldest allowed timestamp and cut out all those before it.
-			let index = find_index(&metric, self.base_timestamp, new_base_timestamp);
-
-			*metric = metric.iter_mut()
-				.skip(index)
-				.map(|dp| {
-					dp.delta_timestamp -= delta;
-					*dp
-				})
-				.collect();
-		}
-
-		self.base_timestamp = new_base_timestamp;
-
-		Ok(())
-	}
-}
-
-#[derive(Clone, Copy)]
-struct Datapoint {
-	delta_timestamp: u32,
-	value: f32
-}
-
-impl Datapoint {
-	fn new(base_timestamp: i64, value: f32) -> Result<Self, Error> {
-		Ok(Self {
-			delta_timestamp: u32::try_from(now_millis() - base_timestamp)
-				.map_err(Error::Timestamp)?,
-			value
-		})
-	}
-
-	fn make_absolute(self, base_timestamp: i64) -> (f32, i64) {
-		(self.value, base_timestamp + self.delta_timestamp as i64)
-	}
-}
-
-fn find_index(slice: &[Datapoint], base_timestamp: i64, timestamp: i64) -> usize {
-	slice.binary_search_by_key(&timestamp, |datapoint| {
-		base_timestamp + datapoint.delta_timestamp as i64
-	}).unwrap_or_else(|index| index)
-}
-
-/// Get the current unix timestamp in milliseconds.
-fn now_millis() -> i64 {
-	chrono::Utc::now().timestamp_millis()
-}
-
-#[test]
-fn test() {
-	let mut database = Database::new();
-
-	database.push("test", 1.0).unwrap();
-	database.push("test", 2.5).unwrap();
-	database.push("test", 2.0).unwrap();
-	database.push("test 2", 1.0).unwrap();
-
-	let mut keys: Vec<_> = database.keys_starting_with("test").collect();
-	keys.sort();
-
-	assert_eq!(keys, ["test", "test 2"]);
-	assert_eq!(database.keys_starting_with("test ").collect::<Vec<_>>(), ["test 2"]);
-}
diff --git a/utils/grafana-data-source/src/lib.rs b/utils/grafana-data-source/src/lib.rs
deleted file mode 100644
index eacb0c59df38d..0000000000000
--- a/utils/grafana-data-source/src/lib.rs
+++ /dev/null
@@ -1,96 +0,0 @@
-// Copyright 2019-2020 Parity Technologies (UK) Ltd.
-// This file is part of Substrate.
-
-// Substrate is free software: you can redistribute it and/or modify
-// it under the terms of the GNU General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-
-// Substrate is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU General Public License for more details.
-
-// You should have received a copy of the GNU General Public License
-// along with Substrate.  If not, see <http://www.gnu.org/licenses/>.
-
-//! [Grafana] data source server
-//!
-//! To display node statistics with [Grafana], this module exposes a `run_server` function that
-//! starts up a HTTP server that conforms to the [`grafana-json-data-source`] API. The
-//! `record_metrics` macro can be used to pass metrics to this server.
-//!
-//! [Grafana]: https://grafana.com/
-//! [`grafana-json-data-source`]: https://github.com/simPod/grafana-json-datasource
-
-#![warn(missing_docs)]
-
-use lazy_static::lazy_static;
-use parking_lot::RwLock;
-
-mod types;
-mod server;
-#[cfg(not(target_os = "unknown"))]
-pub mod networking;
-mod database;
-
-use database::Database;
-pub use server::run_server;
-use std::num::TryFromIntError;
-
-lazy_static! {
-	// The `RwLock` wrapping the metrics database.
-	static ref DATABASE: RwLock<Database> = RwLock::new(Database::new());
-}
-
-/// Write metrics to `METRICS`.
-#[macro_export]
-macro_rules! record_metrics(
-	($($key:expr => $value:expr,)*) => {
-		if cfg!(not(target_os = "unknown")) {
-			$crate::record_metrics_slice(&[
-				$( ($key, $value as f32), )*
-			])
-		} else {
-			Ok(())
-		}
-	}
-);
-
-/// Write metrics to `METRICS` as a slice. Intended to be only used via `record_metrics!`.
-pub fn record_metrics_slice(metrics: &[(&str, f32)]) -> Result<(), Error> {
-	let mut database = crate::DATABASE.write();
-
-	for &(key, value) in metrics.iter() {
-		database.push(key, value)?;
-	}
-
-	Ok(())
-}
-
-/// Error type that can be returned by either `record_metrics` or `run_server`.
-#[derive(Debug, derive_more::Display, derive_more::From)]
-pub enum Error {
-	/// Hyper internal error.
-	Hyper(hyper::Error),
-	/// Serialization/deserialization error.
-	Serde(serde_json::Error),
-	/// Http request error.
-	Http(hyper::http::Error),
-	/// Timestamp error.
-	Timestamp(TryFromIntError),
-	/// i/o error.
-	Io(std::io::Error)
-}
-
-impl std::error::Error for Error {
-	fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
-		match self {
-			Error::Hyper(error) => Some(error),
-			Error::Serde(error) => Some(error),
-			Error::Http(error) => Some(error),
-			Error::Timestamp(error) => Some(error),
-			Error::Io(error) => Some(error)
-		}
-	}
-}
diff --git a/utils/grafana-data-source/src/server.rs b/utils/grafana-data-source/src/server.rs
deleted file mode 100644
index 8ef5e0378478c..0000000000000
--- a/utils/grafana-data-source/src/server.rs
+++ /dev/null
@@ -1,160 +0,0 @@
-// Copyright 2019-2020 Parity Technologies (UK) Ltd.
-// This file is part of Substrate.
-
-// Substrate is free software: you can redistribute it and/or modify
-// it under the terms of the GNU General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-
-// Substrate is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU General Public License for more details.
-
-// You should have received a copy of the GNU General Public License
-// along with Substrate.  If not, see <http://www.gnu.org/licenses/>.
-
-use serde::{Serialize, de::DeserializeOwned};
-use hyper::{Body, Request, Response, header, service::{service_fn, make_service_fn}, Server};
-use chrono::{Duration, Utc};
-use futures_util::{FutureExt, TryStreamExt, future::{Future, select, Either}};
-use futures_timer::Delay;
-use crate::{DATABASE, Error, types::{Target, Query, TimeseriesData, Range}};
-
-async fn api_response(req: Request<Body>) -> Result<Response<Body>, Error> {
-	match req.uri().path() {
-		"/search" => {
-			map_request_to_response(req, |target: Target| {
-				// Filter and return metrics relating to the target
-				DATABASE.read()
-					.keys_starting_with(&target.target)
-					.collect::<Vec<_>>()
-			}).await
-		},
-		"/query" => {
-			map_request_to_response(req, |query: Query| {
-				let metrics = DATABASE.read();
-
-				let Query {
-					range: Range { from, to },
-					max_datapoints, ..
-				} = query;
-
-				// Return timeseries data related to the specified metrics
-				query.targets.iter()
-					.map(|target| {
-						let datapoints = metrics.datapoints_between(&target.target, from, to, max_datapoints)
-							.unwrap_or_else(Vec::new);
-
-						TimeseriesData {
-							target: target.target.clone(), datapoints
-						}
-					})
-					.collect::<Vec<_>>()
-			}).await
-		},
-		_ => Ok(Response::new(Body::empty())),
-	}
-}
-
-async fn map_request_to_response<Req, Res, T>(req: Request<Body>, transformation: T) -> Result<Response<Body>, Error>
-	where
-		Req: DeserializeOwned,
-		Res: Serialize,
-		T: Fn(Req) -> Res + Send + Sync + 'static
-{
-	let body = req.into_body()
-		.map_ok(|bytes| bytes.to_vec())
-		.try_concat()
-		.await
-		.map_err(Error::Hyper)?;
-
-	let req = serde_json::from_slice(body.as_ref()).map_err(Error::Serde)?;
-	let res = transformation(req);
-	let string = serde_json::to_string(&res).map_err(Error::Serde)?;
-
-	Response::builder()
-		.header(header::CONTENT_TYPE, "application/json")
-		.body(Body::from(string))
-		.map_err(Error::Http)
-}
-
-/// Given that we're not using hyper's tokio feature, we need to define out own executor.
-#[derive(Clone)]
-pub struct Executor;
-
-#[cfg(not(target_os = "unknown"))]
-impl<T> hyper::rt::Executor<T> for Executor
-	where
-		T: Future + Send + 'static,
-		T::Output: Send + 'static,
-{
-	fn execute(&self, future: T) {
-		async_std::task::spawn(future);
-	}
-}
-
-/// Start the data source server.
-#[cfg(not(target_os = "unknown"))]
-pub async fn run_server(mut address: std::net::SocketAddr) -> Result<(), Error> {
-	use async_std::{net, io};
-	use crate::networking::Incoming;
-
-	let listener = loop {
-		let listener = net::TcpListener::bind(&address).await;
-		match listener {
-			Ok(listener) => {
-				log::info!("Grafana data source server started at {}", address);
-				break listener
-			},
-			Err(err) => match err.kind() {
-				io::ErrorKind::AddrInUse | io::ErrorKind::PermissionDenied if address.port() != 0 => {
-					log::warn!(
-						"Unable to bind grafana data source server to {}. Trying random port.",
-						address
-					);
-					address.set_port(0);
-					continue;
-				},
-				_ => return Err(err.into()),
-			}
-		}
-	};
-
-	let service = make_service_fn(|_| {
-		async {
-			Ok::<_, Error>(service_fn(api_response))
-		}
-	});
-
-	let server = Server::builder(Incoming(listener.incoming()))
-		.executor(Executor)
-		.serve(service)
-		.boxed();
-
-	let every = std::time::Duration::from_secs(24 * 3600);
-	let clean = clean_up(every, Duration::weeks(1))
-		.boxed();
-
-	let result = match select(server, clean).await {
-		Either::Left((result, _)) => result.map_err(Into::into),
-		Either::Right((result, _)) => result
-	};
-
-	result
-}
-
-#[cfg(target_os = "unknown")]
-pub async fn run_server(_: std::net::SocketAddr) -> Result<(), Error> {
-	Ok(())
-}
-
-/// Periodically remove old metrics.
-async fn clean_up(every: std::time::Duration, before: Duration) -> Result<(), Error> {
-	loop {
-		Delay::new(every).await;
-
-		let oldest_allowed = (Utc::now() - before).timestamp_millis();
-		DATABASE.write().truncate(oldest_allowed)?;
-	}
-}
diff --git a/utils/grafana-data-source/src/types.rs b/utils/grafana-data-source/src/types.rs
deleted file mode 100644
index 960fc787e3eb2..0000000000000
--- a/utils/grafana-data-source/src/types.rs
+++ /dev/null
@@ -1,50 +0,0 @@
-// Copyright 2019-2020 Parity Technologies (UK) Ltd.
-// This file is part of Substrate.
-
-// Substrate is free software: you can redistribute it and/or modify
-// it under the terms of the GNU General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-
-// Substrate is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU General Public License for more details.
-
-// You should have received a copy of the GNU General Public License
-// along with Substrate.  If not, see <http://www.gnu.org/licenses/>.
-
-use serde::{Serialize, Deserialize};
-
-#[derive(Serialize, Deserialize)]
-pub struct Target {
-	pub target: String,
-}
-
-#[derive(Serialize, Deserialize)]
-pub struct Query {
-	#[serde(rename = "maxDataPoints")]
-	pub max_datapoints: usize,
-	pub targets: Vec<Target>,
-	pub range: Range,
-}
-
-#[derive(Serialize, Deserialize)]
-pub struct Range {
-	#[serde(deserialize_with = "date_to_timestamp_ms")]
-	pub from: i64,
-	#[serde(deserialize_with = "date_to_timestamp_ms")]
-	pub to: i64,
-}
-
-// Deserialize a timestamp via a `DateTime<Utc>`
-fn date_to_timestamp_ms<'de, D: serde::Deserializer<'de>>(timestamp: D) -> Result<i64, D::Error> {
-	Deserialize::deserialize(timestamp)
-		.map(|date: chrono::DateTime<chrono::Utc>| date.timestamp_millis())
-}
-
-#[derive(Serialize, Deserialize)]
-pub struct TimeseriesData {
-	pub target: String,
-	pub datapoints: Vec<(f32, i64)>
-}
diff --git a/utils/grafana-data-source/test/src/main.rs b/utils/grafana-data-source/test/src/main.rs
deleted file mode 100644
index 53deaffc3beb6..0000000000000
--- a/utils/grafana-data-source/test/src/main.rs
+++ /dev/null
@@ -1,44 +0,0 @@
-// Copyright 2019-2020 Parity Technologies (UK) Ltd.
-// This file is part of Substrate.
-
-// Substrate is free software: you can redistribute it and/or modify
-// it under the terms of the GNU General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-
-// Substrate is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU General Public License for more details.
-
-// You should have received a copy of the GNU General Public License
-// along with Substrate.  If not, see <http://www.gnu.org/licenses/>.
-
-use grafana_data_source::{run_server, record_metrics};
-use std::time::Duration;
-use rand::Rng;
-use futures::{future::join, executor};
-
-async fn randomness() {
-	loop {
-		futures_timer::Delay::new(Duration::from_secs(1)).await;
-
-		let random = rand::thread_rng().gen_range(0.0, 1000.0);
-
-		let result = record_metrics!(
-			"random data" => random,
-			"random^2" => random * random,
-		);
-
-		if let Err(error) = result {
-			eprintln!("{}", error);
-		}
-	}
-}
-
-fn main() {
-	executor::block_on(join(
-		run_server("127.0.0.1:9955".parse().unwrap()),
-		randomness()
-	)).0.unwrap();
-}
diff --git a/utils/prometheus/Cargo.toml b/utils/prometheus/Cargo.toml
index a4bf0aa52273e..d335505d58cfe 100644
--- a/utils/prometheus/Cargo.toml
+++ b/utils/prometheus/Cargo.toml
@@ -1,7 +1,7 @@
 [package]
-description = "Prometheus endpoint server"
-name = "prometheus-endpoint"
-version = "2.0.0"
+description = "Prometheus exporter server"
+name = "prometheus-exporter"
+version = "0.8.0"
 license = "GPL-3.0"
 authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2018"
diff --git a/utils/prometheus/README.md b/utils/prometheus/README.md
index 67199143fcdd6..c6746d573d602 100644
--- a/utils/prometheus/README.md
+++ b/utils/prometheus/README.md
@@ -1,5 +1,5 @@
 # Substrate Prometheus Exporter
-![grants](./photo_2019-12-13_16-32-53.jpg)
+
 ## Introduction
 
 Prometheus is one of the most widely used monitoring tool for managing highly available services supported by [Cloud Native Computing Foundation](https://www.cncf.io/). By providing Prometheus metrics in Substrate, node operators can easily adopt widely used display/alert tools such as Grafana and Alertmanager without setting-up/operating external Prometheus push gateways (which is an antipattern in the first place) through RPC connections. Easy access to such monitoring tools will benefit parachain developers/operators and validators to have much higher availability of their services.
@@ -14,12 +14,11 @@ Start Prometheus
 
 ## Metrics
 
-substrate can report and serve the Prometheus metrics, which in their turn can be consumed by Prometheus collector(s).
+Substrate can report and serve the Prometheus metrics, which in their turn can be consumed by Prometheus collector(s).
 
 This functionality is disabled by default.
 
-To enable the Prometheus metrics, set in your cli command (--prometheus_external, --prometheus-port ). 
-Metrics will be served under /metrics on 9955 port by default.
+Metrics will be served under /metrics on 9615 port by default.
 
 
 ## Start Prometheus
@@ -32,7 +31,7 @@ Then edit `prometheus.yml` and add `jobs` :
 ```yaml
       - job_name: kusama
           static_configs:
-          - targets: ['localhost:9955']
+          - targets: ['localhost:9615']
             labels:
               instance: local-validator
 ```
diff --git a/utils/prometheus/photo_2019-12-13_16-32-53.jpg b/utils/prometheus/photo_2019-12-13_16-32-53.jpg
deleted file mode 100644
index cdf44f88fb623..0000000000000
Binary files a/utils/prometheus/photo_2019-12-13_16-32-53.jpg and /dev/null differ
diff --git a/utils/prometheus/src/lib.rs b/utils/prometheus/src/lib.rs
index 7cb18b220028c..fc53d89ba0301 100644
--- a/utils/prometheus/src/lib.rs
+++ b/utils/prometheus/src/lib.rs
@@ -18,7 +18,7 @@ extern crate lazy_static;
 
 use futures_util::{FutureExt, future::Future};
 use hyper::http::StatusCode;
-use hyper::{Server, Body, Request, Response, service::{service_fn, make_service_fn}};
+use hyper::{Server, Body, Response, service::{service_fn, make_service_fn}};
 use prometheus::{Encoder, Opts, TextEncoder, core::Atomic};
 use std::net::SocketAddr;
 #[cfg(not(target_os = "unknown"))]
@@ -27,12 +27,12 @@ mod networking;
 pub use prometheus::core::{
 	GenericGauge as Gauge, AtomicF64 as F64, AtomicI64 as I64, AtomicU64 as U64
 };
+pub use prometheus::{Registry, Error as PrometheusError};
 pub use lazy_static::lazy_static;
 
 pub fn create_gauge<T: Atomic + 'static>(name: &str, description: &str) -> Gauge<T> {
 	let opts = Opts::new(name, description);
 	let gauge = Gauge::with_opts(opts).expect("Creating Gauge Failed");
-	prometheus::register(Box::new(gauge.clone())).expect("Registering gauge failed");
 	gauge
 }
 
@@ -43,20 +43,23 @@ pub enum Error {
 	/// Http request error.
 	Http(hyper::http::Error),
 	/// i/o error.
-	Io(std::io::Error)
+	Io(std::io::Error),
+	#[display(fmt = "Prometheus exporter port {} already in use.", _0)]
+	PortInUse(SocketAddr)
 }
 impl std::error::Error for Error {
 	fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
 		match self {
 			Error::Hyper(error) => Some(error),
 			Error::Http(error) => Some(error),
-			Error::Io(error) => Some(error)
+			Error::Io(error) => Some(error),
+			Error::PortInUse(_) => None
 		}
 	}
 }
 
-async fn request_metrics(req: Request<Body>) -> Result<Response<Body>, Error> {
-	let metric_families = prometheus::gather();
+async fn request_metrics(registry: Registry) -> Result<Response<Body>, Error> {
+	let metric_families = registry.gather();
 	let mut buffer = vec![];
 	let encoder = TextEncoder::new();
 	encoder.encode(&metric_families, &mut buffer).unwrap();
@@ -84,31 +87,21 @@ impl<T> hyper::rt::Executor<T> for Executor
 /// Initializes the metrics context, and starts an HTTP server
 /// to serve metrics.
 #[cfg(not(target_os = "unknown"))]
-pub  async fn init_prometheus(mut prometheus_addr: SocketAddr) -> Result<(), Error>{
-	use async_std::{net, io};
+pub async fn init_prometheus(prometheus_addr: SocketAddr, registry: Registry) -> Result<(), Error>{
 	use networking::Incoming;
-	let listener = loop {
-		let listener = net::TcpListener::bind(&prometheus_addr).await;
-		match listener {
-			Ok(listener) => {
-				log::info!("Prometheus server started at {}", prometheus_addr);
-				break listener
-			},
-			Err(err) => match err.kind() {
-				io::ErrorKind::AddrInUse | io::ErrorKind::PermissionDenied if prometheus_addr.port() != 0 => {
-					log::warn!(
-						"Prometheus metric port {} already in use.", prometheus_addr.port()
-					);
-					prometheus_addr.set_port(0);
-					continue;
-				},
-				_ => return Err(err.into())
-			}
-		}
-	};
-	let service = make_service_fn(|_| {
-		async {
-			Ok::<_, Error>(service_fn(request_metrics))
+	let listener = async_std::net::TcpListener::bind(&prometheus_addr)
+		.await
+		.map_err(|_| Error::PortInUse(prometheus_addr))?;
+
+	log::info!("Prometheus server started at {}", prometheus_addr);
+
+	let service = make_service_fn(move |_| {
+		let registry = registry.clone();
+
+		async move {
+			Ok::<_, hyper::Error>(service_fn(move |_| {
+				request_metrics(registry.clone())
+			}))
 		}
 	});