You can use Mitch to update Mitch, that's what the itch.io version does. However, the F-Droid version is built by F-Droid themselves, their build servers run with a specific schedule, and their builds are signed with a different key, which makes the F-Droid and itch.io builds incompatible.

There are two ways for me to fix this: one is to allow users to do a manual backup & restore to be able to switch between the two different versions, second is to set up Reproducible Builds so that F-Droid and itch.io produce identical APKs.

Both of these require some extra work and I can't promise that I'll be able to do it soon.

Well, F-Droid was updated :) Does the itch.io Mitch upgrade itself successfully? I think I tried reinstalling itself but failed.

I do believe a backup system would be great, but I guess we should have another ticket for it? :)

There is a ticket for backups: https://todo.sr.ht/~gardenapple/mitch/51

I made one for repro builds: https://todo.sr.ht/~gardenapple/mitch/61