diff --git a/x/slashing/keeper/keeper.go b/x/slashing/keeper/keeper.go
index 1e622f56eb..0c1182da9f 100644
--- a/x/slashing/keeper/keeper.go
+++ b/x/slashing/keeper/keeper.go
@@ -45,7 +45,7 @@ func NewKeeper(cdc codec.BinaryCodec, legacyAmino *codec.LegacyAmino, storeServi
 			sb,
 			types.ValidatorSigningInfoKeyPrefix,
 			"validator_signing_info",
-			sdk.ConsAddressKey,
+			sdk.LengthPrefixedAddressKey(sdk.ConsAddressKey), // nolint: staticcheck // sdk.LengthPrefixedAddressKey is needed to retain state compatibility
 			codec.CollValue[types.ValidatorSigningInfo](cdc),
 		),
 	}
diff --git a/x/slashing/types/signing_info.go b/x/slashing/types/signing_info.go
index 8e9519d51d..18443311aa 100644
--- a/x/slashing/types/signing_info.go
+++ b/x/slashing/types/signing_info.go
@@ -3,7 +3,6 @@ package types
 import (
 	"time"
 
-	"github.com/cosmos/cosmos-sdk/codec"
 	sdk "github.com/cosmos/cosmos-sdk/types"
 )
 
@@ -21,9 +20,3 @@ func NewValidatorSigningInfo(
 		MissedBlocksCounter: missedBlocksCounter,
 	}
 }
-
-// UnmarshalValSigningInfo unmarshals a validator signing info from a store value
-func UnmarshalValSigningInfo(cdc codec.Codec, value []byte) (signingInfo ValidatorSigningInfo, err error) {
-	err = cdc.Unmarshal(value, &signingInfo)
-	return signingInfo, err
-}