The latest version of Thunderbird can be downloaded from Softpedia
Mozilla officially released Thunderbird 22.0 Beta 1 for Linux, an email and RSS client, featuring just a few security fixes.Unlike the Beta version of Mozilla Firefox, the new Thunderbird release features more basic changes and fixes.
Highlights of Mozilla Thunderbird 22.0 Beta 1:
• Subjects with mixed ASCII and MIME words are now correctly displayed;
• Build system hooks have been added;
• 2x images have been added for HiDPI Thunderbird UI;
• Compose windows are no longer recycled;
• A bottom border has been added to the Tab toolbar.
Check out the official release notes for a complete list of changes and updates.
Download Mozilla Thunderbird 22.0 Beta 1 for Linux from Softpedia.
Download Mozilla Thunderbird 22.0 Beta 1 for Windows from Softpedia.
Download Mozilla Thunderbird 22.0 Beta 1 for Mac OS from Softpedia.
Remember that this is a beta version and it should NOT be installed on production machines. It is intended for testing purposes only