The latest version of Thunderbird can be downloaded from Softpedia
Mozilla has released Thunderbird 28.0 Alpha 2 Earlybird, an email and RSS client, for all the available platforms, including Linux.Soon after the launch of the latest stable version of Thunderbird, 24.1.1, the Mozilla developers have already released a new development version for the application.
As usual, there aren't any specific details about this build, but you can download the archive and run the application without having to install anything. It should run without any problems, but you will have to be careful because it will use your existing profiles.
Don't forget to check out our review of the RSS function of Thunderbird.
Download Mozilla Thunderbird 28.0 Alpha 2 for Linux
Download Mozilla Thunderbird 28.0 Alpha 2 for Windows
Download Mozilla Thunderbird 28.0 Alpha 2 for Mac OS
Remember that this is a development version and it should NOT be installed on production machines. It is intended for testing purposes only.