”Repository […] changed its Version value from […] to […]”
This means that the major and minor version you are running is no longer current and a newer version is available from the repo. From that point, you should no longer receive further updates from the repository (when running apt-get upgrade) unless you allow the updater to switch to the newer version.
To resolve this issue, just run the following command:
In Debian 11 Bullseye the security suite is now named bullseye-security instead of bullseye/updates. So you need to locate the following debian-security lines in the /etc/apt/sources.list file:
deb http://security.debian.org/debian-security bullseye/updates maindeb-src http://security.debian.org/debian-security bullseye/updates main
And replace them with these ones:
deb https://deb.debian.org/debian-security/ bullseye-security maindeb-src https://deb.debian.org/debian-security/ bullseye-security main
Perform a Minimal System Upgrade first
apt updateapt upgrade --without-new-pkgs
If apt-listchanges is installed, press Q to close its pager with release notes.
You will be asked to confirm to stop running services.