She referred to Thunderbird developers spending large efforts responding to changes to Mozilla technologies, while Firefox was paying a tax to support Thunderbird development. On December 1, 2015, Mozilla Executive Chair Mitchell Baker announced in a company-wide memo that Thunderbird development needs to be uncoupled from Firefox.

The new development model shifted to Mozilla offering only 'Extended Support Releases', which deliver security and maintenance updates, while allowing the community to take over the development of new features. On July 6, 2012, Mozilla announced the company was dropping the priority of Thunderbird development because the continuous effort to extend Thunderbird's feature set was mostly fruitless. On December 7, 2004, version 1.0 was released, and received more than 500,000 downloads in its first three days of release, and 1,000,000 in 10 days. The project strategy was modeled after that of the Mozilla Firefox web browser. Thunderbird is a free, open source, cross-platform email, news, RSS, and chat client developed by the Mozilla Foundation. Type Email client, news client, feed reader Operating system Windows XP SP2 or later OS X 10.6 or later Linux Written in C, C++, JavaScript,CSS,XUL, XBL Official Homepage for thunderbird ĭeveloper(s) Mozilla Foundation (formerly Mozilla Messaging) Windows (xp vista 7 8 10) all languages versions 102.6.1 64 bit

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