Debian 4 binary i386 upgrade to latest Debian on a server

Solution 1:

Don't.

First, as a general rule, don't make big changes on a system that you don't know how to use yet. (That is, if you're not familiar with Debian aside from copypasting commands, it's not time to do release upgrades yet.)

Second, don't make big changes on a system if you don't know what it's running. Is it a web server, a mail server, an IRC server? If you don't know what's in there, then you won't be able to know whether anything broke after the changes.

(Third, don't install GUI packages on servers. It might not harm having some light desktop environment in there, but you should instead manage it remotely via SSH most of the time, and the desktop will just waste resources.)

(Fourth, you should've made a backup first.)

Finally, I'm not sure whether you can upgrade Debian straight from 4 to 11 in the first place. You might need to do a fresh install anyway.

Debian went through big architectural changes across this range of 7 releases. If you upgrade version by version it might still work; if you try upgrading straight to buster or bullseye, I strongly suspect you'll just end up with an unbootable system that you'll have to reinstall anyway. In fact I'm not even sure if apt/dpkg from Debian 4 will even recognize the package formats from now.

Many libraries have changed their APIs, and some completely removed. If the server is running some program that itself is no longer in the repositories (or indeed one that never was), it won't get updated for the new libraries. This still works out better on Debian than some other distros, because many libraries can have different versions installed side by side and the old packages may just stick around after upgrades, but they also might not.

And you probably might want a fresh install for various other reasons – changing the filesystem to a more modern one, installing 64-bit instead of 32-bit, and so on.

So if you want the server to work like used to then keep it as-is for now, and spend some time figuring out what's in there. Then do a clean install of latest Debian and try to move all that stuff to the new server, and once it's working clean out the old one.

On the other hand, if you want to use the server for completely new tasks, then give it a completely new installation as well. Just make a full backup of the old system first, e.g. create a tarball or raw image of the entire disk.