The fourth beta version of Mac OS X 10.6.7 has been seeded to developers, three weeks after the first beta was issued.

There are no known issues with the new release and developers have been asked to focus testing on the Mac App Store as well as Airport, Bonjour, SMB file sharing and Graphics Drivers, Apple Insider reports.

The first beta of Mac OS X 10.6.7 was issued on 20 January, just two weeks after Mac OS X 10.6.6 was released to the public.

While the final version of OS X 10.6.7 is unlikely to bring any changes as significant as the addition of the Mac App Store, it is unclear whether there will be any further Snow Leopard updates or whether Apple will move its development efforts on to Mac OS X 10.7 Lion, which is due to be released this summer.