The 2.0 version depends on the iflytofsuipc.exe provided by the ifly team to access all ifly functions. Please download the tool, and run it beside FS.
The button click may be the lights which are switched using ifly-fsuipc-offsets to check if the offsets are exposed correctly. I know that this check doesn't work 100% correctly. Sometimes the error message comes up even though everything is working fine. I'll try to find a better way once I have more time - maybe at the end of the month.
This is possible but I haven't been able to try it out yet. I'll give it a look as soon as possible.
Which functions aren't working anymore? Just provide one or two and I can look it up easier in the documentation.