winswitch sees when a xpra child dies, and throws it out of its session list.
It would be nice to have a command for xpra (menu on client side, commandline on server side?) to have a running xpra process execve() itself again; this way winswitch would keep its child, and newer versions could simply be upgraded in-place.
Of course, a similar thing might be done for winswitch ...
r475 ensures that "upgrading" or using "--use-display" works properly and winswitch uses this to upgrade xpra sessions running older versions: winswitch r4764
this ticket has been moved to: https://github.com/Xpra-org/xpra/issues/70