diff --git a/zebra-consensus/src/block.rs b/zebra-consensus/src/block.rs
index c86c3983de3..f1623b7897e 100644
--- a/zebra-consensus/src/block.rs
+++ b/zebra-consensus/src/block.rs
@@ -25,7 +25,6 @@ use tracing::Instrument;
 use zebra_chain::{
     block::{self, Block},
     parameters::Network,
-    parameters::NetworkUpgrade,
     transparent,
     work::equihash,
 };
@@ -83,9 +82,8 @@ where
     S::Future: Send + 'static,
 {
     pub fn new(network: Network, state_service: S) -> Self {
-        let branch = NetworkUpgrade::Sapling.branch_id().unwrap();
-        let script_verifier = script::Verifier::new(state_service.clone(), branch);
-        let transaction_verifier = transaction::Verifier::new(script_verifier);
+        let transaction_verifier =
+            transaction::Verifier::new(network, script::Verifier::new(state_service.clone()));
 
         Self {
             network,
@@ -176,6 +174,7 @@ where
                     .call(transaction::Request::Block {
                         transaction: transaction.clone(),
                         known_utxos: known_utxos.clone(),
+                        height,
                     });
                 async_checks.push(rsp);
             }
diff --git a/zebra-consensus/src/script.rs b/zebra-consensus/src/script.rs
index cad3c6b093e..a4bc2e5c592 100644
--- a/zebra-consensus/src/script.rs
+++ b/zebra-consensus/src/script.rs
@@ -2,7 +2,7 @@ use std::{collections::HashMap, future::Future, pin::Pin, sync::Arc};
 
 use tracing::Instrument;
 
-use zebra_chain::{parameters::ConsensusBranchId, transaction::Transaction, transparent};
+use zebra_chain::{parameters::NetworkUpgrade, transaction::Transaction, transparent};
 use zebra_state::Utxo;
 
 use crate::BoxError;
@@ -21,27 +21,34 @@ use crate::BoxError;
 #[derive(Debug, Clone)]
 pub struct Verifier<ZS> {
     state: ZS,
-    branch: ConsensusBranchId,
 }
 
 impl<ZS> Verifier<ZS> {
-    pub fn new(state: ZS, branch: ConsensusBranchId) -> Self {
-        Self { state, branch }
+    pub fn new(state: ZS) -> Self {
+        Self { state }
     }
 }
 
 /// A script verification request.
-///
-/// Ideally, this would supply only an `Outpoint` and the unlock script,
-/// rather than the entire `Transaction`, but we call a C++
-/// implementation, and its FFI requires the entire transaction.
-/// At some future point, we could investigate reducing the size of the
-/// request.
 #[derive(Debug)]
 pub struct Request {
+    /// Ideally, this would supply only an `Outpoint` and the unlock script,
+    /// rather than the entire `Transaction`, but we call a C++
+    /// implementation, and its FFI requires the entire transaction.
+    ///
+    /// This causes quadratic script verification behavior, so
+    /// at some future point, we need to reform this data.
     pub transaction: Arc<Transaction>,
     pub input_index: usize,
+    /// A set of additional UTXOs known in the context of this verification request.
+    ///
+    /// This allows specifying additional UTXOs that are not already known to the chain state.
     pub known_utxos: Arc<HashMap<transparent::OutPoint, Utxo>>,
+    /// The network upgrade active in the context of this verification request.
+    ///
+    /// Because the consensus branch ID changes with each network upgrade,
+    /// it has to be specified on a per-request basis.
+    pub upgrade: NetworkUpgrade,
 }
 
 impl<ZS> tower::Service<Request> for Verifier<ZS>
@@ -68,13 +75,16 @@ where
             transaction,
             input_index,
             known_utxos,
+            upgrade,
         } = req;
         let input = &transaction.inputs()[input_index];
+        let branch_id = upgrade
+            .branch_id()
+            .expect("post-Sapling NUs have a consensus branch ID");
 
         match input {
             transparent::Input::PrevOut { outpoint, .. } => {
                 let outpoint = *outpoint;
-                let branch_id = self.branch;
 
                 let span = tracing::trace_span!("script", ?outpoint);
                 let query =
diff --git a/zebra-consensus/src/transaction.rs b/zebra-consensus/src/transaction.rs
index 894e6450548..27c6417a52c 100644
--- a/zebra-consensus/src/transaction.rs
+++ b/zebra-consensus/src/transaction.rs
@@ -14,7 +14,8 @@ use tower::{Service, ServiceExt};
 use tracing::Instrument;
 
 use zebra_chain::{
-    parameters::NetworkUpgrade,
+    block,
+    parameters::{Network, NetworkUpgrade},
     transaction::{self, HashType, Transaction},
     transparent,
 };
@@ -28,6 +29,7 @@ mod check;
 /// Asynchronous transaction verification.
 #[derive(Debug, Clone)]
 pub struct Verifier<ZS> {
+    network: Network,
     script_verifier: script::Verifier<ZS>,
     // spend_verifier: groth16::Verifier,
     // output_verifier: groth16::Verifier,
@@ -40,8 +42,11 @@ where
     ZS::Future: Send + 'static,
 {
     // XXX: how should this struct be constructed?
-    pub fn new(script_verifier: script::Verifier<ZS>) -> Self {
-        Self { script_verifier }
+    pub fn new(network: Network, script_verifier: script::Verifier<ZS>) -> Self {
+        Self {
+            network,
+            script_verifier,
+        }
     }
 }
 
@@ -54,15 +59,22 @@ where
 pub enum Request {
     /// Verify the supplied transaction as part of a block.
     Block {
+        /// The transaction itself.
         transaction: Arc<Transaction>,
         /// Additional UTXOs which are known at the time of verification.
         known_utxos: Arc<HashMap<transparent::OutPoint, zs::Utxo>>,
+        /// The height of the block containing this transaction, used to
+        /// determine the applicable network upgrade.
+        height: block::Height,
     },
     /// Verify the supplied transaction as part of the mempool.
     Mempool {
+        /// The transaction itself.
         transaction: Arc<Transaction>,
         /// Additional UTXOs which are known at the time of verification.
         known_utxos: Arc<HashMap<transparent::OutPoint, zs::Utxo>>,
+        /// The active NU in the context of this verification.
+        upgrade: NetworkUpgrade,
     },
 }
 
@@ -91,15 +103,20 @@ where
             unimplemented!();
         }
 
-        let (tx, known_utxos) = match req {
+        let (tx, known_utxos, upgrade) = match req {
             Request::Block {
                 transaction,
                 known_utxos,
-            } => (transaction, known_utxos),
+                height,
+            } => {
+                let upgrade = NetworkUpgrade::current(self.network, height);
+                (transaction, known_utxos, upgrade)
+            }
             Request::Mempool {
                 transaction,
                 known_utxos,
-            } => (transaction, known_utxos),
+                upgrade,
+            } => (transaction, known_utxos, upgrade),
         };
 
         let mut redjubjub_verifier = crate::primitives::redjubjub::VERIFIER.clone();
@@ -135,6 +152,7 @@ where
                         // feed all of the inputs to the script verifier
                         for input_index in 0..inputs.len() {
                             let rsp = script_verifier.ready_and().await?.call(script::Request {
+                                upgrade,
                                 known_utxos: known_utxos.clone(),
                                 transaction: tx.clone(),
                                 input_index,
@@ -146,10 +164,11 @@ where
 
                     check::has_inputs_and_outputs(&tx)?;
 
+                    // TODO: rework this code
                     let sighash = tx.sighash(
-                        NetworkUpgrade::Sapling, // TODO: pass this in
-                        HashType::ALL,           // TODO: check these
-                        None,                    // TODO: check these
+                        upgrade,
+                        HashType::ALL, // TODO: check these
+                        None,          // TODO: check these
                     );
 
                     if let Some(joinsplit_data) = joinsplit_data {