The Mozilla development team has announced the release of a public beta of Thunderbird 5.0. The Beta channel release is the Mozilla Messaging project's first after adopting a versioning model similar to that used by Google for its Chrome web browser – Mozilla is also using this model for Firefox development.

Aimed at developers, testers and early adopters, the latest beta of Thunderbird sees its version number skip from 3.3 all the way to 5.0, completely bypassing 4.0. This move brings Thunderbird's version number in line with that of the recent beta of Firefox 5.



Thunderbird 5.0 Beta 1 on Mac OS X Building on version 3.3 Alpha 3, changes in Thunderbird 5.0 Beta 1 include user interface improvements, a new troubleshooting information page to help users diagnose problems, and enhancements to Tabs, which can now be reordered and dragged to different windows. A new Add-ons Manager and Extension management API has been added, however, the developers note that its user interface will change before the final release. Also included is support for displaying attachment sizes next to attachments, default plug-ins support in RSS feeds, and a number of bug fixes.

The developers say that this first rapid release of the open source email client is "considered to be stable", although some add-ons may not work properly. Thunderbird 5.0 Beta 1 supports both 32- and 64-bit Intel-based Mac OS X systems – systems with PowerPC (PPC) processors are no longer supported.

As with all development releases, use in production environments and on mission critical systems is not advised. Users testing the release are encouraged to provide feedback and report any bugs that they find.

Details about the pre-release version of Thunderbird 5 can be found in the release notes. Users can download the Beta channel release of Thunderbird 5, labelled 5.0b1, for Windows, Mac OS X and Linux from the Thunderbird Beta web page.

Thunderbird binaries are released under the Mozilla Thunderbird End-User Software License Agreement and the source code is released under disjunctive tri-licensing that includes the Mozilla Public Licence, GPLv2 and LGPLv2.1. The latest stable release of Thunderbird is version 3.1.10, a maintenance and security update from late April.

See also:

Thunderbird Beta Now Available, a Mozilla Developer Center news post.

(crve)