Moodle 2.6.7 release notes
From MoodleDocs
This version of Moodle is no longer supported. You are encouraged to upgrade to a supported version of Moodle.
Releases > Moodle 2.6.7 release notes
Release date: January 12, 2015
Here is the full list of fixed issues in 2.6.7.
Security issues
A number of security related issues were resolved. Details of these issues will be released after a period of approximately one week to allow system administrators to safely update to the latest version.