Zimbra is a server and client technology for next-generation enterprise messaging and collaboration (email, group calendar, contacts, etc). It features a browser-based AJAX client with search, shared calendar, and mail that is integrated with contacts and calendar, and support for Outlook, iCal, Mail.app, contacts, and offline mode. Administrators benefit from online move, back-up, and recovery of individual or groups of mailboxes, compatibility with existing LDAP directories., native hierarchical storage management and clustering, Web services integration with existing enterprise applications, and integrated anti-spam and anti-virus.

Changes

This is the first release in the 5.0.0 release cycle. New features include IM, Tasks, Standard Client autocompletion, and keyboard navigation. Updates have been made to migration wizards and apple/outlook connectors.

URL: Zimbra offers Open Source email server software and shared calendar for Linux and the Mac