As of July 2012, Thunderbird has transitioned to a new governance model, with new features being developed by the broader free software and open source community, and security fixes and improvements handled by Mozilla.
Thunderbird is a free, open-source, cross-platform e-mail and news (NNTP) client developed by the Mozilla Foundation. The project strategy is modeled after Mozilla Firefox, a project aimed at creating a Web browser.
- Certain messages caused corruption of the drafts summary database.
- "edit as new message" on a received message pre-filled the sender as the composing identity.
- Disposition-Notification-To could not be used in mail.compose.other.header
- Various security fixes
- OS X 10.6 or later