diff --git a/helpers/test_helpers.go b/helpers/test_helpers.go
index fa7b6d648bd0..5f71e24a8cc1 100644
--- a/helpers/test_helpers.go
+++ b/helpers/test_helpers.go
@@ -6,9 +6,11 @@ import (
 
 	"github.com/tendermint/tendermint/crypto"
 
+	"github.com/cosmos/cosmos-sdk/client"
 	sdk "github.com/cosmos/cosmos-sdk/types"
 	"github.com/cosmos/cosmos-sdk/types/simulation"
-	authtypes "github.com/cosmos/cosmos-sdk/x/auth/types"
+	"github.com/cosmos/cosmos-sdk/types/tx/signing"
+	authsign "github.com/cosmos/cosmos-sdk/x/auth/signing"
 )
 
 // SimAppChainID hardcoded chainID for simulation
@@ -18,31 +20,58 @@ const (
 )
 
 // GenTx generates a signed mock transaction.
-func GenTx(msgs []sdk.Msg, feeAmt sdk.Coins, gas uint64, chainID string, accnums []uint64, seq []uint64, priv ...crypto.PrivKey) authtypes.StdTx {
-	fee := authtypes.StdFee{ //nolint:staticcheck // SA1019: authtypes.StdFee is deprecated
-		Amount: feeAmt,
-		Gas:    gas,
-	}
-
-	sigs := make([]authtypes.StdSignature, len(priv)) //nolint:staticcheck // SA1019: authtypes.StdSignature is deprecated
+func GenTx(gen client.TxGenerator, msgs []sdk.Msg, feeAmt sdk.Coins, gas uint64, chainID string, accnums []uint64, seq []uint64, priv ...crypto.PrivKey) (sdk.Tx, error) {
+	sigs := make([]signing.SignatureV2, len(priv))
 
 	// create a random length memo
 	r := rand.New(rand.NewSource(time.Now().UnixNano()))
 
 	memo := simulation.RandStringOfLength(r, simulation.RandIntBetween(r, 0, 100))
 
+	signMode := gen.SignModeHandler().DefaultMode()
+
+	for i, p := range priv {
+		sigs[i] = signing.SignatureV2{
+			PubKey: p.PubKey(),
+			Data: &signing.SingleSignatureData{
+				SignMode: signMode,
+			},
+		}
+	}
+
+	tx := gen.NewTxBuilder()
+	err := tx.SetMsgs(msgs...)
+	if err != nil {
+		return nil, err
+	}
+	err = tx.SetSignatures(sigs...)
+	if err != nil {
+		return nil, err
+	}
+	tx.SetMemo(memo)
+	tx.SetFeeAmount(feeAmt)
+	tx.SetGasLimit(gas)
 	for i, p := range priv {
 		// use a empty chainID for ease of testing
-		sig, err := p.Sign(authtypes.StdSignBytes(chainID, accnums[i], seq[i], fee, msgs, memo))
+		signerData := authsign.SignerData{
+			ChainID:         chainID,
+			AccountNumber:   accnums[i],
+			AccountSequence: seq[i],
+		}
+		signBytes, err := gen.SignModeHandler().GetSignBytes(signMode, signerData, tx.GetTx())
 		if err != nil {
 			panic(err)
 		}
-
-		sigs[i] = authtypes.StdSignature{ //nolint:staticcheck // SA1019: authtypes.StdSignature is deprecated
-			PubKey:    p.PubKey().Bytes(),
-			Signature: sig,
+		sig, err := p.Sign(signBytes)
+		if err != nil {
+			panic(err)
+		}
+		sigs[i].Data.(*signing.SingleSignatureData).Signature = sig
+		err = tx.SetSignatures(sigs...)
+		if err != nil {
+			panic(err)
 		}
 	}
 
-	return authtypes.NewStdTx(msgs, fee, sigs, memo)
+	return tx.GetTx(), nil
 }
diff --git a/simd/cmd/genaccounts.go b/simd/cmd/genaccounts.go
index d5b4ce67dcbe..5dddc2ee7858 100644
--- a/simd/cmd/genaccounts.go
+++ b/simd/cmd/genaccounts.go
@@ -39,8 +39,8 @@ contain valid denominations. Accounts may optionally be supplied with vesting pa
 		Args: cobra.ExactArgs(2),
 		RunE: func(cmd *cobra.Command, args []string) error {
 			clientCtx := client.GetClientContextFromCmd(cmd)
-			depCdc := clientCtx.Codec
-			cdc := clientCtx.JSONMarshaler.(codec.Marshaler)
+			depCdc := clientCtx.JSONMarshaler
+			cdc := depCdc.(codec.Marshaler)
 
 			serverCtx := server.GetServerContextFromCmd(cmd)
 			config := serverCtx.Config
diff --git a/test_helpers.go b/test_helpers.go
index 6ba55f418a93..758b84d4b616 100644
--- a/test_helpers.go
+++ b/test_helpers.go
@@ -17,6 +17,7 @@ import (
 	dbm "github.com/tendermint/tm-db"
 
 	bam "github.com/cosmos/cosmos-sdk/baseapp"
+	"github.com/cosmos/cosmos-sdk/client"
 	"github.com/cosmos/cosmos-sdk/codec"
 	"github.com/cosmos/cosmos-sdk/simapp/helpers"
 	sdk "github.com/cosmos/cosmos-sdk/types"
@@ -312,11 +313,12 @@ func CheckBalance(t *testing.T, app *SimApp, addr sdk.AccAddress, balances sdk.C
 // the parameter 'expPass' against the result. A corresponding result is
 // returned.
 func SignCheckDeliver(
-	t *testing.T, cdc *codec.Codec, app *bam.BaseApp, header abci.Header, msgs []sdk.Msg,
+	t *testing.T, txGen client.TxGenerator, app *bam.BaseApp, header abci.Header, msgs []sdk.Msg,
 	accNums, seq []uint64, expSimPass, expPass bool, priv ...crypto.PrivKey,
 ) (sdk.GasInfo, *sdk.Result, error) {
 
-	tx := helpers.GenTx(
+	tx, err := helpers.GenTx(
+		txGen,
 		msgs,
 		sdk.Coins{sdk.NewInt64Coin(sdk.DefaultBondDenom, 0)},
 		helpers.DefaultGenTxGas,
@@ -325,8 +327,8 @@ func SignCheckDeliver(
 		seq,
 		priv...,
 	)
-
-	txBytes, err := cdc.MarshalBinaryBare(tx)
+	require.NoError(t, err)
+	txBytes, err := txGen.TxEncoder()(tx)
 	require.Nil(t, err)
 
 	// Must simulate now as CheckTx doesn't run Msgs anymore
@@ -361,10 +363,12 @@ func SignCheckDeliver(
 // GenSequenceOfTxs generates a set of signed transactions of messages, such
 // that they differ only by having the sequence numbers incremented between
 // every transaction.
-func GenSequenceOfTxs(msgs []sdk.Msg, accNums []uint64, initSeqNums []uint64, numToGenerate int, priv ...crypto.PrivKey) []authtypes.StdTx {
-	txs := make([]authtypes.StdTx, numToGenerate)
+func GenSequenceOfTxs(txGen client.TxGenerator, msgs []sdk.Msg, accNums []uint64, initSeqNums []uint64, numToGenerate int, priv ...crypto.PrivKey) ([]sdk.Tx, error) {
+	txs := make([]sdk.Tx, numToGenerate)
+	var err error
 	for i := 0; i < numToGenerate; i++ {
-		txs[i] = helpers.GenTx(
+		txs[i], err = helpers.GenTx(
+			txGen,
 			msgs,
 			sdk.Coins{sdk.NewInt64Coin(sdk.DefaultBondDenom, 0)},
 			helpers.DefaultGenTxGas,
@@ -373,10 +377,13 @@ func GenSequenceOfTxs(msgs []sdk.Msg, accNums []uint64, initSeqNums []uint64, nu
 			initSeqNums,
 			priv...,
 		)
+		if err != nil {
+			break
+		}
 		incrementAllSequenceNumbers(initSeqNums)
 	}
 
-	return txs
+	return txs, err
 }
 
 func incrementAllSequenceNumbers(initSeqNums []uint64) {