diff --git a/src/lib/rpcClient.spec.ts b/src/lib/rpcClient.spec.ts
index 469c505..a3f262b 100644
--- a/src/lib/rpcClient.spec.ts
+++ b/src/lib/rpcClient.spec.ts
@@ -209,4 +209,77 @@ describe('RPCClient', () => {
     // Verify the response is defined
     expect(result).toBeDefined()
   })
+
+  describe('blockResults validator updates', () => {
+    const blockResults = (validatorUpdates: unknown) => ({
+      jsonrpc: '2.0',
+      id: 1,
+      result: {
+        height: '1',
+        txs_results: null,
+        finalize_block_events: [],
+        validator_updates: validatorUpdates,
+        consensus_param_updates: null,
+      },
+    })
+
+    it('decodes the cometbft v1 flattened pub_key shape', async () => {
+      nock(mockRpcUris[0])
+        .get('/block_results')
+        .query(true)
+        .reply(
+          200,
+          blockResults([
+            {
+              power: '3469906',
+              pub_key_bytes: 'fZqZqbnw0nQBHe76t9qIcvOyyHjoMH3upoHsUqRvcBU=',
+              pub_key_type: 'ed25519',
+            },
+          ])
+        )
+
+      const client = new RPCClient(mockRpcUris[0])
+      const result = await client.blockResults(1)
+
+      expect(result.validatorUpdates).toHaveLength(1)
+      expect(result.validatorUpdates[0].pubkey.algorithm).toBe('ed25519')
+      expect(result.validatorUpdates[0].votingPower).toBe(3469906n)
+    })
+
+    it('still decodes the legacy nested pub_key shape', async () => {
+      nock(mockRpcUris[0])
+        .get('/block_results')
+        .query(true)
+        .reply(
+          200,
+          blockResults([
+            {
+              power: '100',
+              pub_key: {
+                type: 'tendermint/PubKeyEd25519',
+                value: 'fZqZqbnw0nQBHe76t9qIcvOyyHjoMH3upoHsUqRvcBU=',
+              },
+            },
+          ])
+        )
+
+      const client = new RPCClient(mockRpcUris[0])
+      const result = await client.blockResults(1)
+
+      expect(result.validatorUpdates).toHaveLength(1)
+      expect(result.validatorUpdates[0].votingPower).toBe(100n)
+    })
+
+    it('handles blocks without validator updates', async () => {
+      nock(mockRpcUris[0])
+        .get('/block_results')
+        .query(true)
+        .reply(200, blockResults(null))
+
+      const client = new RPCClient(mockRpcUris[0])
+      const result = await client.blockResults(1)
+
+      expect(result.validatorUpdates).toHaveLength(0)
+    })
+  })
 })
diff --git a/src/lib/rpcClient.ts b/src/lib/rpcClient.ts
index b616f8e..84d5adc 100644
--- a/src/lib/rpcClient.ts
+++ b/src/lib/rpcClient.ts
@@ -243,9 +243,39 @@ function decodeBlockResults(
     rpcBlockResult.result.end_block_events = end_block_events
   }
 
+  rpcBlockResult.result.validator_updates =
+    rpcBlockResult.result.validator_updates?.map(normalizeValidatorUpdate) ??
+    null
+
   return Responses.decodeBlockResults(rpcBlockResult)
 }
 
+const PUB_KEY_AMINO_TYPES: Record<string, string> = {
+  ed25519: 'tendermint/PubKeyEd25519',
+  secp256k1: 'tendermint/PubKeySecp256k1',
+}
+
+// cometbft v1 flattened `pub_key` into `pub_key_bytes`/`pub_key_type`, which
+// the cosmjs decoder rejects. Blocks carrying a validator set change would
+// otherwise stall the sync worker forever.
+function normalizeValidatorUpdate(
+  update: RpcValidatorUpdate
+): RpcValidatorUpdate {
+  if (update.pub_key !== undefined || update.pub_key_bytes === undefined) {
+    return update
+  }
+
+  const type = PUB_KEY_AMINO_TYPES[update.pub_key_type ?? '']
+  if (type === undefined) {
+    throw Error(`unknown pubkey type ${update.pub_key_type}`)
+  }
+
+  return {
+    power: update.power,
+    pub_key: { type, value: update.pub_key_bytes },
+  }
+}
+
 interface Header {
   header: {
     version: {
@@ -287,6 +317,16 @@ interface RpcBlockResultsResponse {
   begin_block_events: RpcEvent[] | null
   end_block_events: RpcEvent[] | null
   finalize_block_events: RpcEvent[] | null
+  validator_updates: RpcValidatorUpdate[] | null
+}
+
+interface RpcValidatorUpdate {
+  power?: string
+  /** pre-cometbft-v1 shape */
+  pub_key?: { type: string; value: string }
+  /** cometbft v1 flattened shape */
+  pub_key_bytes?: string
+  pub_key_type?: string
 }
 
 interface RpcTxData {