Apple is in a hurry to improve the new version of Mac OS X 10.6.8 since we already have the third beta version in just 3 weeks. 10K531 is the build of the new version and the installation package is around 1 GB if we are talking about the Combo version or only 450 MB if we are talking about the Delta version. Apple asks developers to focus on exactly the same things as before, ie: AirPort, graphics card drivers, Mac App Store, the way networks work, QuickTime and VPN.
Considering that Mac OS X Lion is scheduled to be released this summer, it is possible that Apple will release Mac OS X 10.6.8 shortly after WWDC. Mac OS X 10.6.8 can only be downloaded by you if you are a Mac application developer.
