sorry if that's been answered somewhere else, but I couldn't find the answer on the forum or website.
I have Deluge Thin Client installed on a Raspberry Pi (Debian bullseye) for a few years, and it works just fine. I have version 1.3.15 but I want to update because I like new shiny things.
Somehow when doing apt-get, I get an error that the mirror does not have a Release file. Here's the mirror used:
That's an ubuntu PPA mirror. Latest deluge isn't even on debain sid I see, but anyway, i'd check if available on pypi('pip3 install deluge', with 'sudo' optionally) i.e. they have arm versions for some packages/deps, but I don't know specifically about your setup, sorry.
I quickly googled it, and seems there are some issues, but one noted that main issue fixed now if using 64 bit OS though. Here are instructions(later in thread), but mind you it's somewhat elaborate:
I don't believe that's a normal case, but always keep backups in general, here your deluge profile e.g '/var /lib/deluge/.config/deluge', or wherever is on your end.