Originally launched as Minotaur shortly after Phoenix (the original name for Mozilla Firefox), the project failed to gain momentum. With the success of the Mozilla Firefox, however, demand increased for a mail client to go with it, and the work on Minotaur was revived under the new name of Thunderbird, and migrated to the new toolkit developed by the Firefox team.
Significant work on Thunderbird restarted with the announcement that from version 1.5 onwards, the main Mozilla suite would be designed around separate applications using this new toolkit. This contrasts with the previous all-in-one approach, and will hopefully lead to more efficient and maintainable code, as well as allowing users to mix and match the Mozilla applications with alternatives.
The original Thunderbird logo was just a modified Firebird logo: with a simple shifting of hue value from red to blue. In 2004, together with the change of Firefox's visual identity by Jon Hicks, a more professional logo that is currently in use was introduced.
Parts of this table are based on the Thunderbird roadmap.
|Old Version||Current Version||Future Version|
|Gecko version||Version||Release date||Significant changes|
|1.5||0.1||July 28, 2003|
|0.2||September 3, 2003|
|0.3||October 15, 2003|
|1.6||0.4||December 5, 2003|
|0.5||February 9, 2004|
|1.7||0.6||May 3, 2004||Pinstripe theme for Mac OS X, Windows installer, better junk mail handling, IMAP IDLE and LDAP version 3 support.|
|0.7||June 16, 2004||Smaller download size, improved IMAP support, updated extension and theme managers|
|0.7.1||June 28, 2004||Bugfix release.|
|0.7.2||July 8, 2004||Vulnerability patch (Windows only).|
|0.7.3||August 4, 2004||Vulnerability patch.|
|0.8||September 14, 2004||Improved Privacy Controls, Global Inbox, RSS/Atom Integration, Improved data migration. Improved spell checker support.|
|0.9||November 3, 2004||More RSS integration. Favorite folders. Menu and dialog polish. Message list groups. Virtual folders.|
|1.0 RC1||December 1, 2004||Bug fixing. Improved theme. Polish work.|
|1.0||December 7, 2004||Official Version 1.0 release.|
|1.0.2 1||March 21, 2005||Stability and security improvements.|
|1.0.5 2||July 13, 2005||Vulnerability patch.|
|1.0.6||July 19, 2005||Fix for extension API regression.|
|1.0.7||September 29, 2005||Vulnerability patch and regression fix.|
|1.0.8||April 21, 2006||Vulnerability patch and regression fix. End-of-life of 1.0.x product line.|
|1.8||1.1 Alpha 1||June 2, 2005||Stability improvement and security fixes.|
|1.1 Alpha 2||July 15, 2005||The second alpha (intended for testers) for upcoming 1.5 release.|
|1.5 Beta 1||September 9, 2005||New update system (binary patch).|
|1.5 Beta 2||October 7, 2005||Improvements to automated update system, website rendering and performance. Several security fixes.|
|1.5 RC1||November 5, 2005||First release candidate.|
|1.5 RC2||December 21, 2005||Second release candidate.|
|1.5||January 11, 2006||Official Version 1.5 release. Identical to 1.5 RC2.|
|184.108.40.206||April 21, 2006||Stability improvement and security fixes.|
|220.127.116.11 3||June 1, 2006||Native support for Intel-based Macintosh computers, aka universal binary. Stability improvement and security fixes.|
|18.104.22.168||July 27, 2006||Stability improvement and security fixes.|
|22.214.171.124 4||September 14, 2006||Stability improvement and security fixes.|
|126.96.36.199||November 8, 2006||Stability improvement and security fixes.|
|188.8.131.52||December 19, 2006||Stability improvement and security fixes.|
|184.108.40.206||March 1, 2007||Stability improvement and security fixes.|
|220.127.116.11||May 30, 2007||Stability improvement and security fixes.|
|18.104.22.168||August 23, 2007||Stability improvement and security fixes.|
|22.214.171.124||December 19, 2007||Stability improvement and security fixes. End-of-life of 1.5.0.x product line.|
|1.8.1||2.0 Alpha 1||July 28, 2006||Message Tags. Folder Views including favorite folders. Improved new mail notification alerts. New Windows installer based on Nullsoft Scriptable Install System. Find As You Type in the message pane. New combined and improved Add-ons manager for extensions and themes. Updates to the extension system to provide enhanced security and to allow for easier localization of extensions.|
|2.0 Beta 1||December 12, 2006||Improved theme. Session history navigation. Improved offline management. Folder summary popups. Improved performance in saved search folders. Improved filing tools.|
|2.0 Beta 2||January 23, 2007||Feature complete beta|
|2.0 RC1||April 6, 2007||Release Candidate (informally available since March 27, see Developers' announcement)|
|April 18, 2007||Windows Vista support, message tags, new visual theme, improved extension support, improved new email notifications, folder summary pop-ups, find text in messages search tool, new Windows installer, easy access to popular email services, advanced folder views, session history navigation, and saved search folder performance. (Identical to 2.0 RC 1, and corresponding zipped nightly is dated 2007032620)|
|June 14, 2007||Korean locale was added, along with stability improvement and security fixes.|
|July 19, 2007||Stability improvement and security fixes.|
|August 1, 2007||Stability improvement and security fixes.|
|November 14, 2007||Hebrew locale was added, along with stability improvement and security fixes.|
|February 26, 2008||Afrikaans and Ukrainian locales were added, along with stability improvement and security fixes.|
|May 1, 2008||Stability improvement and security fixes.|
|July 23, 2008||Stability improvement and security fixes.|
|September 25, 2008||Security fixes.|
|November 19, 2008||Stability improvement and security fixes.|
|December 30, 2008||Stability improvement and security fixes.|
|March 18, 2009||Stability improvement and security fixes.|
|June 22, 2009||Stability improvement and security fixes.|
|126.96.36.199||August 20, 2009||Stability improvement and security fixes.|
|188.8.131.52||March 15, 2010|
|1.9||3.0 Alpha 1||May 13, 2008||First Alpha of Mozilla Thunderbird 3, also known as Shredder Alpha 1.|
|3.0 Alpha 2||August 12, 2008||Second Alpha of Mozilla Thunderbird 3, also known as Shredder Alpha 2.|
|1.9.1||3.0 Alpha 3||October 14, 2008||Third Alpha of Mozilla Thunderbird 3, also known as Shredder Alpha 3.|
|3.0 Beta 1||December 9, 2008||First Beta of Mozilla Thunderbird 3.|
|3.0 Beta 2||February 26, 2009||Second Beta of Mozilla Thunderbird 3.|
|3.0 Beta 3||July 21, 2009||Third Beta of Mozilla Thunderbird 3, major features added, theme redesigns.|
|3.0 Beta 4||September 22, 2009||Fourth Beta of Mozilla Thunderbird 3, new Gloda search functionality enabled.|
|3.0 RC1||November 24, 2009||First Release Candidate.|
|3.0 RC2||December 1, 2009||Second Release Candidate.|
|3.0||December 8, 2009|
|3.0.1||January 20, 2010||Off-cycle stability update.|
|3.0.2||February 25, 2010||Off-cycle stability update.|
|3.0.3||March 1, 2010||Off-cycle stability update.|
|3.0.4||March 30, 2010||Off-cycle stability update.|
|1.9.2||3.1 Alpha 1||February 3, 2010||First Alpha of Mozilla Thunderbird 3.1 (Lanikai Alpha 1).|
|3.1 Beta 1||March 10, 2010||First Beta of Mozilla Thunderbird 3.1.|
|3.1 Beta 2||Second Beta of Mozilla Thunderbird 3.1.|
|3.1||est. June 2010||Final Version of Mozilla Thunderbird 3.1.|
Note (2): There were no version 1.0.3 and 1.0.4 since the bugs/issues affected Firefox only.
Note (3): There was no version 184.108.40.206.
Note (4): There was no version 220.127.116.11.
Note (5): There were no versions 18.104.22.168, 22.214.171.124 and 126.96.36.199.
Note (6): There were no versions 188.8.131.52 and 184.108.40.206.
Note (7): There were no versions 220.127.116.11 and 18.104.22.168.
Note (8): There was no version 22.214.171.124.
Note (9): There was no version 126.96.36.199.
Note (10): There was no version 188.8.131.52.
Thunderbird 2: 
Thunderbird 3 no longer supports versions of Windows prior to Windows 2000 (e.g., Windows 95, 98, ME and NT) and Mac OS X versions prior to 10.4 Tiger. Linux requirements have also changed. 
On December 23, 2004, the Project Lightning was announced for tightly integrating calendar functionality (scheduling, tasks, etc.) into Thunderbird. Lightning is just a project name, but not a product name. Lightning 0.1 was released on March 14, 2006. The current version is 0.9, which was released on September 23, 2008.
Also on October 11, 2006, Qualcomm and the Mozilla Foundation announced that "future versions of Eudora will be based upon the same technology platform as the open source Mozilla Thunderbird email program." The project is code-named Penelope. An unofficial Eudora/Penelope forum is accessible via web or newsreader.
On July 26, 2007, the Mozilla Foundation announced that Thunderbird would be developed by an independent organization, because the Mozilla Corporation (the for profit portion of Mozilla) is focusing on Mozilla Firefox development. This change is being done in order to stimulate development in Thunderbird, which has been neglected during the Mozilla focus on Firefox.
On September 17, 2007, the Mozilla Foundation announced the funding of a new internet communications initiative with Dr. David Ascher of ActiveState. The purpose of this initiative is "to develop Internet communications software based on the Thunderbird product, code and brand".
On February 19, 2008, Mozilla Messaging started operations as a subsidiary of the Mozilla Foundation responsible for the development of email and similar communications. Its initial focus was on the next major version, Thunderbird 3.0, which was released on December 8, 2009.