Thunderbird 2.0.0.19 was released on December 30th, which was about a week earlier than scheduled. Users will be prompted for an automatic update within the next 72 hours.Those wishing to upgrade now can do so via the Help Menu, Check For Updates option or by downloading the latest release at getthunderbird.com. Thunderbird 2.0.0.19 contains many security fixes and the full details can be found in the Thunderbird 2.0.0.19 Release Notes.
Source: Mozilla Developer News
Downloaded and installed new version ontop of 2.0.0.18 without a hitch. All extensions are working fine.