What’s New

NEW
Multi-Channel Chat: You now can enjoy real time conversation with your contacts, right from your favorite messaging application.
NEW
Do Not Track: This option has been implemented as an addition to Search the Web.
NEW
Ubuntu One is now supported in Filelink - the option to upload large attachments to online storage services.
NEW
New User Interface: Thunderbird is replicating the new look and feel of Mozilla Firefox in an effort to provide a similar user experience across all Mozilla software desktop or mobile and all platforms.
FIXED
Various fixes and performance improvements
FIXED
Various security fixes

Known Issues

Unresolved
If you are unable to view content for your RSS feeds in the Wide View Layout, you can switch to Classic View, or you may need to disable the Lightning Calendar add-on. In both cases, you'll need to restart Thunderbird (see 531397).