Today the Bugzilla project has four releases!
3.0.1 is the first bug-fix release for the 3.0 series. 3.0 was very stable, but 3.0.1 adds a lot of little polish fixes that greatly improve the experience of using Bugzilla.
3.1.1 is our first development release toward Bugzilla 3.2. It has a huge number of new features, but is EXTREMELY UNSTABLE. It has not been tested, and should not be used in a production environment. It may fail in critical ways, or destroy your data. However, it is useful as a feature preview and for testing purposes.
2.22.3 and 2.20.5 are security-fix and critical bug-fix releases for the 2.22 and 2.20 series. If you are using any 2.22 or 2.20 version, we strongly recommend you update to these versions.
All four releases also contain security fixes, and so you should definitely update if you want your installation to remain secure.
Related link: More information (external link)