This is primarily a project from Trustedbird/Milimail who appear to have stopped supporting it a couple of years ago.
Their original project pages are:
- http://adullact.net/plugins/mediawiki/wiki/milimail/index.php/Trustedbird_Project
- http://www.trustedbird.org/
- http://adullact.net/plugins/mediawiki/wiki/milimail/index.php/Out_of_Office
- https://adullact.net/anonscm/git/milimail/milimail.git
We (Open Solutions have fixed a significant number of bugs to make it work with Thunderbird 17 and can confirm that it is working with Dovecot Sieve (2.1.7).
It was and continues to be released under MPL 1.1/GPL 2.0/LGPL 2.1.