Postilion is a mail user agent based upon the popular TkRat program.
Many other features and enhancements have been added to Postilion, ranging from robust support for IMAP in a shared folder environment, to subtle touches which make mail browsing just a bit more pleasant of an experience. This program was made by the users requests.
Great effort has been made to support multiuser environments with support for system wide configurations, mailboxes and address books; shared folders, etc. Many of these features require the use of IMAP mailboxes. When you build Postilion, you will also build an IMAP4rev1 server which you can experiment with. See the "imap" directory for details.
One of the main features of TkRat which has not survived the transition well at all is multi-language interface support (TkRat had built-in support for English, Swedish and Italian). The reason for this is that I have changed much of the text, yet I do not know these languages for translation. Instructions are included for how to do translations, and I solicit any interested party to contribute their translations (please contact me before starting, just so I can coordinate efforts). Postilion currently has support for English, French, German, Italian Dutch and Swedish.