diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1c974e07cd2b..7dc2fca08023 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -47,6 +47,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 * (x/bank) [#6](https://github.com/01builders/cosmos-sdk/pull/6) Change denom index bank migration to noOp.
 * (x/auth) [#7](https://github.com/01builders/cosmos-sdk/pull/7) Support legacy global AccountNumber.
 * (crypto/keyring) [#8](https://github.com/01builders/cosmos-sdk/pull/8) Fix error wrapping in pkg crypto/keyring. Removed `cockroachdb/errors` in favour of `errorsmod.Wrap`.
+* (x/consensus) [#9](https://github.com/01builders/cosmos-sdk/pull/9) Address bug where sending `MsgUpdateParams` to `x/consensus` would overwrite `AppVersion` with zero value. Always use existing `AppVersion` param.
 
 ## [v0.50.11](https://github.com/cosmos/cosmos-sdk/releases/tag/v0.50.11) - 2024-12-16
 
diff --git a/x/consensus/keeper/keeper.go b/x/consensus/keeper/keeper.go
index b239a9ee5ee7..1a8421b8da07 100644
--- a/x/consensus/keeper/keeper.go
+++ b/x/consensus/keeper/keeper.go
@@ -88,6 +88,10 @@ func (k Keeper) UpdateParams(ctx context.Context, msg *types.MsgUpdateParams) (*
 
 	nextParams := params.Update(&consensusParams)
 
+	// NOTE: do not override the version params
+	// consensusParams.Version always has DefaultConsensusParams version: 0
+	// AppVersion is updated by x/upgrade during migrations
+	nextParams.Version = params.Version
 	if err := nextParams.ValidateBasic(); err != nil {
 		return nil, err
 	}