diff --git a/CHANGELOG.md b/CHANGELOG.md
index 85feb853..580a20fa 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -50,6 +50,8 @@
   and `LaunchpadLedger` for more fine-grained access.
 - @cosmjs/math: Add `.multiply` method to `Decimal` class.
 - @cosmjs/tendermint-rpc: Make `BroadcastTxCommitResponse.height` non-optional.
+- @cosmjs/tendermint-rpc: Make `TxProof.proof.leafHash` non-optional because it
+  is always set.
 - @cosmjs/tendermint-rpc: Change type of `GenesisResponse.appState` to
   `Record<string, unknown> | undefined`.
 - @cosmjs/utils: Add `assertDefined`.
diff --git a/packages/tendermint-rpc/src/responses.ts b/packages/tendermint-rpc/src/responses.ts
index 755090d8..9f3ae892 100644
--- a/packages/tendermint-rpc/src/responses.ts
+++ b/packages/tendermint-rpc/src/responses.ts
@@ -188,8 +188,7 @@ export interface TxProof {
   readonly proof: {
     readonly total: number;
     readonly index: number;
-    /** Optional because does not exist in Tendermint 0.25.x */
-    readonly leafHash?: Uint8Array;
+    readonly leafHash: Uint8Array;
     readonly aunts: readonly Uint8Array[];
   };
 }
diff --git a/packages/tendermint-rpc/types/responses.d.ts b/packages/tendermint-rpc/types/responses.d.ts
index 67e2687c..7707c6e1 100644
--- a/packages/tendermint-rpc/types/responses.d.ts
+++ b/packages/tendermint-rpc/types/responses.d.ts
@@ -147,8 +147,7 @@ export interface TxProof {
   readonly proof: {
     readonly total: number;
     readonly index: number;
-    /** Optional because does not exist in Tendermint 0.25.x */
-    readonly leafHash?: Uint8Array;
+    readonly leafHash: Uint8Array;
     readonly aunts: readonly Uint8Array[];
   };
 }