I have updated packages many times after 12.1 release, but I still have 12.0 in debian_version file. I tried to install today printer drivers but it couldn’t get the latest libcupsimage2 2.4.2-3 library on the server although there is 2.4.2-5 already.
How to fix the version? Is it possible that it breaks cupsimage installation?
So 12.1 is out but have you upgraded any of your packages yet? The /etc/debian_version file comes from the base-files package. On my up to date system, it’s showing 12.1 in the file and the package version is 12.4+deb12u1 as I can see from dpkg -l base-files.
Make sure to do an apt update and then do an apt upgrade -s to do a dry-run to see what packages would be upgraded. I’m guessing the base-files package hasn’t been updated.
I've upgraded packages several times. My base-files package has version 12.4. I've tried with apt update and apt upgrade -s and I don't have any package to upgrade. Is it possible that the version is locked somewhere?
I’m not aware of a way to lock an entire system to a major.minor version with Debian, only holding individual packages. What exact version is your base-files? The full string matters.
You could check to see if anything is held with apt-mark showhold.
It is possible that the mirror you have in your sources.list file stopped syncing so to your system is looks like it has no updates. What mirror is your system pointed at?