diff --git a/ably/proto_protocol_message_test.go b/ably/proto_protocol_message_test.go
index 763a731d..68532f5d 100644
--- a/ably/proto_protocol_message_test.go
+++ b/ably/proto_protocol_message_test.go
@@ -25,7 +25,7 @@ func TestProtocolMessageEncodeZeroSerials(t *testing.T) {
 	encoded, err := ablyutil.MarshalMsgpack(msg)
 	assert.NoError(t, err)
 	// expect a 3-element map with both the serial fields set to zero
-	expected := []byte("\x83\xB0id\xA4test\xA9msgSerial\x00")
+	expected := []byte("\x82\xa2id\xa4test\xa9msgSerial\x00")
 	assert.True(t, bytes.Equal(encoded, expected),
 		"unexpected msgpack encoding\nexpected: %x\nactual:   %x", expected, encoded)
 }