Moodle 2.5.1, 2.4.5, 2.3.8 and 2.2.11 are available via the usual open download channels (http://download.moodle.org or Git).
In addition to a number of bug fixes and small improvements, security vulnerabilities have been discovered and fixed. As always, we recommend that you upgrade your sites to these latest versions as soon as possible. All admins of registered Moodle sites will be notified with security issue details.
Upgrading should be very straightforward. Full details about the releases can be found in the release notes:
- Moodle 2.5.1 release notes
- Moodle 2.4.5 release notes
- Moodle 2.3.8 release notes
- Moodle 2.2.11 release notes
Note that 2.2.11 is the final release in the 2.2 branch and that the 2.3 branch is now supported for security fixes only.