Today, Monday July 13th, Moodle 3.9.1, 3.8.4, 3.7.7, and 3.5.13 have been released. These new minor releases are now available for download via https://download.moodle.org or Git.
The releases include bug-fixes, as well as security improvements, and we recommend that you upgrade your sites as soon as possible. Upgrading should be straightforward.
Administrators of all registered Moodle sites will receive an email with details of the security fixes and we'll publish these more widely shortly.
The release notes for each version can be found here:
Please see the releases page for more details.