Just Released

• Thunderbird 3.1.12 – August 16th
• Thunderbird 3.1.13 – August 30th
• Thunderbird 6.0 – August 16th
• Thunderbird 6.0.1 – August 30th
• Thunderbird 7 Beta 1 – August 26th
• Thunderbird 8 Alpha 2 – August 18th

Coming Soon

• Thunderbird 7 Beta 2 – TBA

Future Releases

• Thunderbird 3.1.14 – September 27th
  
• Thunderbird 7 Final Release – September 27th
• Thunderbird 8 Beta – September 27th*
• Thunderbird 9 Earlybird – September 27th*

* As part of the new Rapid Release Schedule, dates listed for Earlybird and Beta builds reflect when the code merge is to begin. The actual release to that particular channel may vary by several days. See this post for more details.