Flatpak has a concept of a package being end of life, but it seems like this would be useful to be communicated in the AppStream data, i.e. on a release?

Brought up here: elementary/appcenter#1020

A commit in flatpak can be marked end-of-life, as in it is no longer expected to get updates, and with that it can have a custom message or redirect to a new package replacing it. Appcenter should expose this information in the UI in some form.

The basic API docs are here:

• http://flatpak.github.io/flatpak/reference/html/FlatpakTransaction.html#FlatpakTransaction-end-of-lifed

• http://flatpak.github.io/flatpak/reference/html/FlatpakRemoteRef.html#FlatpakRemoteRef--end-of-life