Apple has seeded Mac OS X 10.6.8 Build 10K537 to developers.
9to5Mac reports that there are no known issues with the update. Developers have been asked to focus on AirPort, Graphics Drivers, Mac App Store, Networking, QuickTime and VPN.
The delta update is 454MB, with the combo update weighing in at 1GB.
Last week at WWDC Apple revealed that it will release Mac OS X 10.7 Lion at some stage in July.
Lion will only be available through the Mac App Store, to the consternation of Snow Leopard users with slow internet connections, as it will be a 4GB download.
There is also some concern among the retail community about the effect a download-only launch on Lion will have on revenues.