Comment 6 for bug 1545296

The crash you are reporting does not concern Ubuntu. That's an error in the packaging of the upstream binary. Generally speaking, it is a very bad idea to install packages from outside repos. I have yet to see an upstream that gets packaging right. Certainly, when they package for about 20 different platforms like xpra does. Again, I advise you to stay away. But please, for heaven's sake, don't waste Ubuntu devs' time reporting bugs in those packages here.

That being said, I believe the error you encountered in upstream binary might be fixed by installing their python-rencode binaries as well.

The valid bug here is only that xpra xenial cannot talk to xpra trusty. I've seen that in jessie-backports to trusty as well. I believe the breakpoint is around version 0.15.0 where this python-rencode code came into play.