The main frequently raised objection to Flatpaks is their space requirements, caused by the need to install not just the apps themselves but also the corresponding runtimes. Since Flatpak applications share the copy of a runtime if they use the same one, this is only an issue for the first few Flatpaks, and after that the required runtimes are generally already present.
What exacerbates the problem though is that each platform (minimal Freedesktop, GNOME, KDE) has versioned runtimes. So for users who have KDE apps installed (which all use version 6.9), installing Avogadro (which still uses version 6.8) adds a whole extra runtime.
I’m going to propose that going forward, we adopt a policy whereby the Avogadro Flatpak aligns with KDE apps for the runtime used, avoiding unnecessary duplication for users.
The key consequence of this is that the Flatpak would use a different, slightly newer version of Qt to the other Avogadro platforms and formats. This should generally not be an issue given the pace of change of Qt, but is worth bearing in mind.
Unlike for the other releases, where we worry about bumping the Qt version because we’re wary of causing problems for users of older OSes, the Flatpak doesn’t have the same concern – new runtimes work fine on older systems on the whole due to the containerization, that’s the whole advantage of the format.
One advantage for us of doing this would be that the Flatpak (in particular the beta version) would then give us some advance testing of Avogadro running against the current Qt version.
If you approve @ghutchis, I’d switch the beta to use 6.9 now, and only switch stable at the next release (1.102 or 2.0). Then, whenever in future the KDE suite bumps the runtime version I’d do similarly, bumping beta immediately and carrying it over to stable only at the next release.