Thank you! That command and file to backup are the kind of info I was after.
And I appreciate the reminder that applications and configs might not work. I plan to test everything after each upgrade (I don’t plan on jumping straight to 24.04).
I do already know the version of TigerVNC, for example, I’m using is not the same as the latest, and I’ve seen it works a bit different on my machines with newer OS versions. Also I seem to remember Firefox needs to be installed as deb not snap or it won’t work with TigerVNC. So I’ll make sure to backup my profile folder for Firefox.
This computer is mostly a file server, I’ll have to do an inventory of what software I’ve used on it over the years.