With the current protocol way of handling previous, the client needs to track the request's return previous flag value when it needs to decide whether to decode the previous value in the response or it.

Doing this ties the decoder with the request made. It would be better for the put/putIfAbsent/replace operations to provide a different status code, say 0x04 for when the operation succeeds and the previous value follows. By doing this, the decode has all it needs to decode in the actual response, rather than having to remember what the request flag was.

This can easily be fixed in Hot Rod 2.0 protocol.