The first incremental update to Mountain Lion, OS X 10.8.1, should be released momentarily. Apple has already announced plans to seed OS X 10.8.2 to members of the AppleSeed customer testing program, and developers should be offered the same treatment soon.
Apple needs all the testing power it can get when OS X 10.8.2 is released as a beta. The company hardly ever tests two different incremental versions of one OS iteration simultaneously.
At most, Apple will test OS X 10.8.2 builds alongside OS X 10.9 builds for next year’s refresh of the Mac operating system. But that’s yet to be confirmed.
As such, OS X 10.8.1 should be released no later than this week, with testing to commence on OS X 10.8.2 around the same time.
It is believed OS X 10.8.2 will be a compatibility release, with 10.8.1 fixing a number of widespread issues with battery life on MacBook computers, networking, and more.