Hi
I had done that and confirmed that the repositories were correct, and done an apt update but then apt search or apt install --reinstall weewx couldn't find it. In the end, I downloaded the Python3 package and installed it manually. I had to update the interceptor plugin but it's all now working on python3. Meanwhile, after a few more apt updates, it is suddenly started showing up again in apt search. I've been using Linux for over 20 years and Debian is my preferred distro. But I can't account for what I saw! I am actually running Debian Bullseye so things are occasionally a little bleeding edge.
I've been running weewx for about 18 months since I got a Aercus Weather Ranger (FineOffset clone). Weewx is great - my site is at
https://wx.whisker.org.uk/ - you can choose between Belchertown, neowx and sofaskin skins.
I noticed another person had a similar issue also, but it seems to be OK now.
Regards
Peter