Hi, thanks for filing this and being willing to give it a second shot :) . I thought I had fixed the crash on login bug last week but it was still happening on windows and I was mostly testing on linux. (I don't have a Mac so hopefully it works on OSX :) It was kind of tricky to figure out but I think it was a combination of godot spamming debug messages and trying to reference some audio files that were not there. I rewrote the audio system with more careful checks and may check this is as a godot demo project.
I fixed this and many other things in a bugfix marathon last night and just updated the version that went along with my last dev blog since there have not been many downloads. The server does check the client version on login so an old version will fail to log in and should say why.