Zarafa Outlook Sharing is a Microsoft Exchange replacement. The Open Source
Collaboration provides an integration with your existing Linux mail server,
native mobile phone support by ActiveSync compatibility and a webaccess with
'Look & Feel' similar to Outlook using Ajax. Including an IMAP4 and a POP3
gateway as well as an iCal/CalDAV gateway, Zarafa can combine the usability
with the stability and flexibility of a Linux server.

The proven Zarafa groupware solution is using MAPI objects, provides a MAPI
client library as well as programming interfaces for C++, PHP and Perl. The
other Zarafa related packages need to be installed to gain all the features
and benefits of Zarafa Outlook Sharing and Open Source Collaboration.