11-12 should be well tested. 12-13 should be well tested. 11-13 may work, but you may be the tester.

I'd step through one at a time.

11 > 12 > 13 is way safer!

No.

By itself, apt will give you headaches.

Debian migrated to new paths for security non-free firmware in repositories from 11 to 12, and apt goes to v3 in 12 to 13, which changes the format of sources. There is a new apt modernize-sources command, but it assumes your paths are correct.

If you know what you're doing, you can do this by correcting the repo paths and do the without-new-packages upgrade, but be prepared to fix apt.

If you're a casual user, maybe stick with 11>12>13.

For fixed-release distros (Debian/Ubuntu), the upgrade path is usually sequential.

The main implication: if you skip, you’re outside the tested upgrade path. That can mean broken packages, orphaned configs, security regressions, or a system that simply won’t boot. Sometimes you can force it and it’ll work, but it’s a gamble...

I’m wouldn’t do it. Debian isn’t something that likes big jumps like that. Consider an immutable distro if you want to be able to leap around that way.

Likely not. I've tried skipping a release once by accident (I didn't pay enough attention) and it ended with a bricked system and a full reinstall. Don't do it.

This is one of those times I'm glad I use a dotfiles repo

Major version changes for any software from the OS right down to a simple notepad app should update as sequentially as possible (11>12>13>etc). Skipping over versions is just asking for trouble, as it's rarely tested throughly.

It might work, but why risk it.

An example: if 12 makes a big database change but you skip over that version, 13 may not recognize the databases left by 11 because 12 had the code to recognize and reformat the old database while that code was seen as unnecessary and removed from 13.

Stuff like this is also why you can't always revert to an older version while keeping the data/databases from the newer software.

It would be great if more effort was put into ensuring a seamless upgrade experience.

Hey. I'm going through this right now. My server was 11, and I wanted to go to 13. I definitely didn't want to get into a situation where the server required hours and hours of repair.

I'm halfway there. The upgrade to 12 went smoothly. The biggest headache was glances, first from the lack of web interface (which I was ready for), and the lack of RAID support (not ready). I might do the switch to 13 next week.

As someone who went through the 12-13 upgrade last week. Do not go directly. I had to rollback twice during the 12-13 upgrade(thank you timeshift) so I couldn't imagine trying to run an 11-13 upgrade.