High Quality Content by WIKIPEDIA articles! OS X Server, formerly Mac OS X Server, was a separately sold Unix server operating system from Apple Inc. architecturally identical to its desktop counterpart OS X—with additional server programs and management and administration tools. As of version 10.7 (Lion), Mac OS X and Mac OS X Server were combined into one release and re-branded as OS X. A separate "server" operating system is no longer sold; the server-specific server applications and work group management and administration software tools from Mac OS X Server are now offered as Server App, an add-on package for OS X sold through the Mac App Store along with Server Admin Tools 10.7, available from the Apple support web site.