Project Debian releases a stable version of its operating system every two years. The last one is Bookworm, and I arrive in June with Linux 6.1 and GNOME 43 in its main edition. During the five years that each version is supported, what they do is, on the one hand, update the packages for existing installations, and, on the other, release new ISO images that contain all of this and are intended for new installations. The last one arrived yesterday Saturday, and it is Debian 12.2.
They have also made Debian 11.8 available to anyone interested, which is the 2021 version with already eight maintenance updates. In the new Debian 12 image, all the updates that have been in Debian since 12.1 have been introduced, which they gave us at the end of June, and among them there are 177 bug fixes and 52 security patches. This is in addition to new versions of some packages, not all, since Debian has a conservative philosophy and does not usually use the most recent versions of any software. They prioritize stability.
Debian 12.2 is not a "new version"
Just like explains the project, something they always do and we repeat, we must keep in mind that this is a point release and it is not a remake of Debian 12, but are updates for some packages. Therefore, it is not necessary to load anything and reinstall from scratch, thinking that this will solve problems that may arise when uploading from one version to another: «Please note that this point release is not a new version of Debian 12, but only updates some of the included packages. There's no need to throw away your old "Bookworm" media. After installation, packages can be updated to current versions using an updated Debian mirror«.
The new images can be downloaded from one of the servers on this link or in this other if you are looking for a Live image.