Apple released an update to Mountain Lion Server called OS X Server 2.1.1, which adds several features and fixes related to DHCP, DNS, and Active Directory. It also updates Profile Manager to add support for managing iOS 6 devices.
The update enables you to administer DHCP service from the Server app. DHCP service had long been part of OS X Server, but Apple removed it from the first Mountain Lion Server builds. Previous to the 2.1.1 update only way to set DHCP was using System Preferences or the command line. The update also enables the Server app to manage email blacklist settings and to set a default NetBoot image.
Active Directory clients can now authenticate to OS X Server's Calendar service. Administrators can now configure DNS entries with second level domains and aliases, and retain DNS and PHP settings when upgrading OS X Server.
(There's more detail on OS X Server 2.1.1 here.)
Apple this year changed its name and version numbering for OS X Server. Although the version of OS X Server that ran on Lion was first called "Mac OS X Server v. 10.7," Apple now refers to it as "OS X Server v. 1.0." The version that runs on Mountain Lion (which is OS X 10.8) is now called "OS X Server v. 2.x."
If you've tried this update