NixOS/nixpkgs — pull request #5 by aszlig (2012-06-05 13:38:21+00:00)
Title: New version of Xpra from the fork

This is because the original version is no longer in development, as stated on
the website at http://code.google.com/p/partiwm/wiki/xpra:

"This project is in deep hibernation; I haven't had time to devote for several
years now. If you are looking for xpra, you may prefer Antoine Martin's fork,
which receives more support. It is available at: http://xpra.org/"

So I guess its safe to switch over to that fork.