Scalable OpenGroupware.org (Inverse edition)
SOGo is fully supported and trusted groupware server with a focus on scalability and open standards. SOGo is released under the GNU GPL/LGPL v2 and above.
SOGo provides a rich AJAX-based Web interface and supports multiple native clients through the use of standard protocols such as CalDAV, CardDAV and GroupDAV, as well as Microsoft ActiveSync.
SOGo is the missing component of your infrastructure; it sits in the middle of your servers to offer your users an uniform and complete interface to access their information. It has been deployed in production environments where thousands of users are involved.
new version 4