The most recent OS X Mountain Lion Server seed, build "12S219N," comes on the heels of Wednesday's Mountain Lion client build "12A206J" and is the latest developer preview to be released in the ongoing beta testing process that is scheduled to yield a gold master ready for public consumption sometime this summer.
A number of issues to be ironed out by developers include installing apps on iOS managed devices, a sporadic Spotlight problem in Xsan and SMTP server authentication in Mail. Also of note is a directory services bug that sees clients failing to bind to non-SSL-enabled Open Directory Servers.
Developers can download OS X Mountain Lion Developer Preview 4 through Apple's Development Center.
The latest seed keeps with the monthly beta updates as the client version of OS X 10.8 Mountain Lion Developer Preview 3 was issued in April, which followed a second preview from mid-March.
Apple's next-generation operating system is set to further blur the lines between iOS and OS X with features like tighter integration with iCloud and geofence location alerts, among many others.
Mountain Lion is expected to be a tentpole topic at this year's WWDC as Apple has promised to show developers the "future of iOS and OS X" at the conference scheduled to start on June 11.