Debian is a free operating system (OS) for your computer. An operating system is the set of basic programs and utilities that make your computer run. Debian provides more than a pure OS: it comes with over 59000 packages, precompiled software bundled up in a nice format for easy installation on your machine.
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?
I'm using http://deb.debian.org/debian mirror, but I was surprised that it didn't download files with apt-get update command. I removed /var/lib/apt/lists directory, and it worked and upgraded to 12.1 :).
File a bug