OS X Server, which is available for download on the Mac App Store for $19.99, has quietly updated this week with a number of bug fixes. Apple notes that it does not disclose, discuss or confirm security issues until a full investigation has occurred and any necessary patches or releases are available.
That said, 9to5Mac does detail some notable changes in this version. For instance, OS X Server’s “Caching” module has been updated to now allow OS X apps to cache their data, locally. Wiki Server has gained support for Apple’s “Retina” displays, and the company notes that it fixed a bug which may have caused some trouble for those upgrading from OS X Lion Server.
For more details see this Apple support document.