No its pretty much perfect seas.

Anything I should look out for, or smooth sailing?

I am using Cinnamon + X11 + Nvidia, everything working as it should. I use Distrobox and Flatpaks for additional packages, so I don’t really touch the base install much but it seems rock solid as expected from Debian.

Previous release had PHP 7.4, new one has 8.2. Nextcloud 24 supports 7.2 - 8.0, 25 supports 7.2 - 8.1 and 26 supports 8.0 - 8.2, which is a bit inconvenient.

To upgrade, I first¹ upgraded Nextcloud to 25, then PHP to 8.2, removed the versioncheck in Nextcloud to accept PHP 8.2 and then upgraded to Nextcloud 26.

Otherwise very smooth - even the usrmerge was absolutely event-free.

¹) of course what I actually did first was upgrade Debian/PHP without checking beforehand and then installing PHP 7.4 from the previous release again.

I did the upgrade procedure to move from 11 to 12. Most things went just fine, but for some reason hplip was uninstalled and I could not print. Manually installing the correct hplip package allowed me to reconfig my printer and that was working again. The other thing that broke is my sound. The sound server changed from Pulse Audio to Pipe Wire. The sound worked with Pipe Wire but it was putting my sound card to sleep. On my motherboard, it must engage some kind of high impedance state because it causes a loud 60HZ hum. The solution was to turn off the feature that sleeps the sound card. It’s a desktop system, not a laptop, so I don’t care about saving battery. The config was actually in the /etc/wireplumber/main.lua.d set of configs. Besides all that, Debian 12 is great, as it has been since I started using it in 1997.