For usenet news groups they offer the latest NNTPS. but the 8.0 release still uses the Mork file format.
The current version of Sea Monkey, version 2.14.1, also still uses Mork for its indexes for both POP and IMAP mail folders (at least).
With contributors all over the world,the client is translated into more than 50 different languages, although email addresses are currently limited to ASCII local parts.
Thunderbird does not yet support SMTPUTF8 (RFC 6531) or Email Address Internationalization.
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." On July 26, 2007, the Mozilla Foundation announced that Thunderbird would be developed by an independent organization, because the Mozilla Corporation (a subsidiary of the foundation) was focusing on Mozilla Firefox development.