Currently XnViewMP flatpak repository (https://github.com/flathub/com.xnview.XnViewMP) is maintained by volunteers, users of your software. Flatpak/Flathub insists that ownership should be held by program author. That would reduce delays after new release. I understand that maintaining one more package format might be problematic, but currently flatpak updates do not require too much work, just three changes: package URL, checksum and link to new release notes. Test packages are built automatically by Flathub Bot on remote server and can be installed locally with single command.
Here are some statistics about XnViewMP installations from Flathub: https://klausenbusk.github.io/flathub-s ... e=installs
Consider taking over maintenance of Flatpak repository
Moderators: helmut, XnTriq, xnview