Thunderbird 5
No not that Thunderbird, but Mozilla Thunderbird 5, their desktop email application, has been released for Windows, Macintosh and Linux, with performance improvements, new features and security fixes.
Mozilla has added over 390 fixes to improve performance, speed, security and stability. Including in the list of new features are tabbed message viewing and an new add-on manager.
To ensure your machines security, you should update to Thunderbird 5 as soon as possible.
Note: that certain Thunderbird extensions/add-ons may not work correctly after the update.
