Shipping with the latest security updates from the Debian Stable (Jessie) software repositories, Univention Corporate Server (UCS) 4.1-4 adds a bunch of interesting improvements and new features to the Linux-based, server-oriented operating system from Univention. Among these, we can mention the implementation of Samba 4.5.1 for better Active Directory compatibility and DRS replication. While the addition of Samba 4.5.1 also improves the printer and file sharing services, a new kernel based on the upstream Linux 4.1 long-term supported series, adds several security updates, overall stability enhancements, as well as support for newer hardware. Another interesting feature is the simplification of the migration to dockerize apps.