The docs (and a few recent posts here on Fedora Discourse) say to upgrade Silverblue with the rpm-ostree command. Example:
rpm-ostree rebase fedora:fedora/35/x86_64/silverblue
Are there any special steps to take to upgrade flatpaks installed from the fedora origin, or are those independent of the Fedora version?
There are no special steps and they will be updated soon after the release.
Flatpaks are versionned independently of the OS even though on Silverblue they follow the Fedora release cycle as they are made from the same sources as the RPM packages.
That’s good to know! The main reason I asked is that at least one of them has a branch name of f34.
The f34 versionned one is the Flatpak Platform (common base for Fedora Flatpaks). The f35 one will be pulled by updated applications and when the last application requesting it gets updated, it will be removed.
I hope that if an upgrade triggers new FlatPak runtimes that the system also cleans away the old packages, cus FlatPak is heavy already.
You can use the following to update your Flatpaks and then remove everything that is not needed anymore:
$ flatpak update && flatpak remove --unused
I don’t know how GNOME Software for Silverblue or Discover for Kinoite does it but I’ll take a look.
I’m running Silverblue v.35. I think GNOME software does updates automatically. But I’m not 100% sure.