The update adds several bug fixes, though the 'What's New' section includes a number of new features that were originally added back in December 2012.
What's newOS X Server is available for $19.99 on the Mac App Store. [Direct Link]
- Fix for administering Profile Manager from iPad mini.
- Support for using bonded or virtual network interfaces in Server.
- Fix for setup failures due to an SSL error.
- Fixes for upgrading from Lion Server.
For information on the security content of this update, please visit: support.apple.com/kb/HT1222