Unable to upgrade KDE using Kubuntu backports

[DaisyLee2010]

Added Kubuntu backports and backports-extra and ran a sudo apt full upgrade.

After system reboot sddm loses theme and session is gone. I dropped to a tty and can see that plasma is broken because libappstreamqt2 is not at a current enough version.

I even tried to reinstall plasma-desktop and get the same result.

[DaisyLee2010]

I think I found the issue. Looks like pop's repos are pinned at 1001 priority in apt. I've wrote a preliminary script to change the priorities around, update the system, then put the priorities back. Needs testing.