Annecdata here, but I didn’t have any significant problems on like 5 servers. I recall there being one minor edge case, but I don’t remember what it was (sorry). But other than that it was really easy. Even my nvidia drivers continued to work (for cuda, not GUI), which was really surprising. ZFS, docker, ssh, nfs, etc. all continued to work without any problems.

If you want to do a test run, create a 12 VM and install your same package list, then upgrade it and see what happens. That could take as little as an hour to do, but more likely a few hours if you want to really take time to inspect everything after the upgrade.

I updated NAS, VPS and Raspberry Pis not so long ago. All when smooth and without issue.

I update my servers very promptly and have never had a problem with a version jump. Apt handles this well.

On a normal setup without leads or crazy customisation, it’ll be a breeze 👍

My desktop is on its third major version upgrade. I don’t pay attention to breaking changes, and somehow I’ve still been made aware of the few packages that require something. Those packages usually include some kind of easy step by step or a script to migrate.

It’s really quite a breeze to upgrade Debian.

Do you run all your services in docker? If yes, the upgrade should be nothing more than the upgrade including switching the docker repo to the new version codename and rebooting

The official docs have everything, though not as well ordered and concise as they could be.

I’ve taken my server from 11 to 12 to 13. Only issue was 11->12 where backports caused some issue that I no longer remember the specifics of (never broke SSH link), so I just don’t fuck with backports anymore. You need to have your shit together for backports, from what I’ve gathered.

12->13 was abs smooth as butter. Extra 3rd party repos weren’t even an issue. One I had to leave “bookworm” because they didn’t have trixie entries; I found it had no trixie entry by looking at the repo itself - it just kept working no problem after the upgrade anyway.
And I have a “stretch” repo I took from 12 to 13 on another server (it’s mongoDB 4.4 for unifi, an abs shitshow of software those bozos cook up)

Anyway tldr docs are good narry a problem will occur.

I recently upgraded my gaming pc from Bookworm to Trixie. It was fairly painless. Had to fiddle with some third party repos, but I anticipated that and read up on them beforehand.

I’ll probably follow the official documentation

I just apt update, apt upgrade, modify my apt sources to point at the new distro, repeat. If something breaks, I’ll go fix it.

I wouldn’t anticipate problems, though.

0.076

Update when you can afford downtime. The update should be painless but you know how it is: things go crazy when they shouldn’t. Every time.

Backup your data: the stuff you can’t just reconstruct.

The go for it. Worst comes to worst: reconstruct the system and applications and reimport the data.

If you have capacity: do it in a VM first.

The upgrade itself is never a problem.

The real problem is when your server is running an old software that breaks after the update.

For example I had an old php/drupal site and it broke after upgrading debian because the upgrade also updated php to a newer version that is not supported by that old version of drupal.

I’ve found that dist upgrades themselves are fine, but it usually breaks something. Last time it was my janky WordPress installation which was using PHP 7.4. The wordpress version was up to date but it wouldn’t use the installed 8.2 php and just broke. In the end I installed a fresh wordpress and copied the data over.

This is why I’ve started running most services as containers inside of an LXC container in Proxmox

I migrated from Ubuntu to Debian, but my workloads were containerized. Went smoothly. But I had backups.