I snapshot my machine, set it to go overnight, went to bed. Woke up, 24% done “Do you want to use the package maintainer’s version?”. Grr. Went smooth though.

How much pain you should expect is easily answered: Expect several things to break and having to do a full reinstall. So back up everything first.

It will probably not happen, but you should always expect the worst (out of the realistic at least…) outcome and be prepared.

Most of my infra is Debian, and I did it without serious incident:

#Update everything to latest
apt update && apt upgrade && apt full-upgrade && apt --purge autoremove
reboot

#Verify that debian_version is 12.x (STOP IF NOT 12!)
cat /etc/debian_version

#Check for any pinned or held packages
apt list '?narrow(?installed, ?not(?origin(Debian)))'
apt-mark showhold

#Swap bookworm for trixie in repo files
sed -i 's/bookworm/trixie/g' /etc/apt/sources.list
sed -i 's/bookworm/trixie/g' /etc/apt/sources.list.d/*

#Carry out update
apt update
apt upgrade --without-new-pkgs -y
apt full-upgrade -y
reboot

#Verify that debian_version is 13.x
cat /etc/debian_version

#Modernize apt sources to v3
apt modernize-sources -y

And then maybe apt update to make sure the updates still work OK.

Sometimes you have to make changes to certain repos that don’t have Trixie manifests, but that’s easy enough to roll back.

Make sure linux headers stay installed. Mine didn’t for some reason and then zfs dkms didn’t compile anymore. All I had to do was install it again, though, so the googling why it didn’t compile was the hard part. The boot disk was luckily just ext.

I’ve yolo’d every major upgrade from debian 8 to 13 without any backups of configs and survived… (dont do that though)

For most desktop systems where you’re not dicking around with files in /etc, there is almost no pain ever

For servers, dealing with the "do you want to install the maintainers version of ____.conf, sucks… trying to remember all the things i put in php.ini is a pain

Probably skill issue

The first sentence gives away, that this is not a technical, but a psychological question. I think most of us know this feeling of this kind of urge, I’d say plan ahead, backup then upgrade. Or -depending on your usecase- a clean install and rebuild satisfies the urge even better. :) (no offense, I did this myself multiple times)

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

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 backed up my configs, made snapshots, and rebuilt each VM from scratch. If I forgot to copy a cron script, i pulled it from the snapshot. It took a full Saturday, but it was a chance to apply everything ive learned the last 3 years and improve some architecture decisions I’d made when i was first learning. With proxmox, you can build a VM that has the basic things you’ll change on every machine (networking, docker, automatic updates, ssh keys, monitoring) and clone it for each server you need.

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

Acronyms, initialisms, abbreviations, contractions, and other phrases which expand to something larger, that I’ve seen in this thread:

[Thread #149 for this comm, first seen 30th Oct 2026, 13:20] [FAQ] [Full list] [Contact] [Source code]

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

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.

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.

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.