All servers are now running OS X 10.10.4 which has a number of performance and security fixes. In addition the discoveryd DNS daemon that has caused lots of DNS related issues on OS X 10.10.x has now been reverted to the true and tested mDNSResponder.
OS X server has been upgraded to 4.1.3
In addition mono was upgraded from version 3.12.1 to 4.0.1 with a number of performance improvements and bug fixes.
Overall the updates should make for a more responsive and secure grid.