TCP/UDP Binding - Using updatewithresponse option for UDP

Hi openHAB community,
after trying several days to configure the binding to update items with the response (using UDP) without success, i set up the IDE for OpenHab 2 development in order to debug the issue. Thanks to the debugger i could figure out 2 Bugs quite fast:
The parameters “timeout” and “blocking” are not read in correctly, looks like a classical copy & paste error.

String timeOutString = (String) config.get("buffersize");
String blockingString = (String) config.get("retryinterval");

As the options “isBlocking” and “updatewithresponse” are both needed, so that updating items with responses could work (nested if clauses), i got a bit further removing these 2 bugs. Unfortunately i still couldn´t manage to actually use the feature, getting my items updated with a UDP response only. Before digging deeper into the code, i thought i rather ask for help here. So my questions are:

  1. How has the udp response to look like? I send JSON formatted strings on change ( {“relay”: “ON”}, {“relay”: “OFF”} )
  2. To which UDP port do i have to send them?
  3. Is this feature supposed to work with UDP at all, or only for TCP?

Hope someone here knows more about the Binding and can help me out!
Cheers,
Martin