I would like to use the latest+greatest Xpra version on Debian Linux (Stretch) and openSUSE Tumbleweed.
FYI: the latest version of xpra is always available in the xpra repositories for all distribution supported, including Debian Stretch.
As for supporting appimage or even flatpak, it would be great but there are a number of issues:
We will need to continue to package for the ~50 platform+distro+arch combinations we support, only adding to the packaging workload and maintenance burden.
- this is not a workable solution for servers, which need to integrate with the system as a service (logind+udev, selinux, printing integration, etc)
On the other hand, it may simplify the issue of supporting out of date distros like centos6.