Kolab is a free groupware based on Postfix, Cyrus IMAP and Roundcube. The groupware includes email, calendars, addressbooks, task management and a wide variety of clients. Since version 3.1 Kolab also supports the standardized CalDAV and CardDAV protocols so that all data can be synced to a phone, tablet or any CalDAV/iCAL client. More than enough to have a closer look.
Kolab is community driven and has enterprise support by Kolab Systems AG. Next to the enterprise version, they also provide community packages for RHEL and CentOS. The source code is available from their Git repositories. An openSUSE Build Service provides additional testing packages for Debian, Fedora, OpenSUSE and Ubuntu.
Unfortunately, the Gentoo support for Kolab seemed to starve for some reason. We only found some deprecated stubs for Kolab 2 with news from years ago. The promising features and the great community of Kolab convinced us to contribute some time to provide new Gentoo packages for recent Kolab versions.
Based on the CentOS packages for Kolab 3.1, we created a Portage overlay with ebuilds that get their sources directly form the Git repositories of Kolab. Wherever possible, we use the existing ebuilds from the Portage main repository and provide additional patches. The overlay can be found in our Gitlab and we are doing our best to push it further to Layman and the Portage main repository.
Detailed instructions about how to install, configure and troubleshoot the Kolab groupware on a Gentoo system can be found in the Dokuwiki. We appreciate any help to further improve the Kolab overlay. Feel free to send us feedback or add issues to Gitlab.