Zarafa Community is an open-source, full-featured mail storage and groupware solution. Zarafa includes a web-based interface for performing mail, address book and calendar functions. The Community Edition can support any number of users via the web-based interface or through a mail client using IMAP/POP3 protocols.
This version does not support the MAPI protocol for admins looking for a drop-in replacement to MS Exchange[TM].
To learn more about this app, click here
Documentation for ClearOS 6 can be found here.
Documentation for ClearOS 7 can be found here.