With the latest 10.5.5 build in developers' hands, Apple is said to have sliced the testing focus in half, from 24 core system components to just 12, people familiar with the matter have revealed.

AppleInsider cites people familiar with the software as noting that, among the components still in need of attention on behalf of the developers are AirPort, graphics drivers, iCal, iChat, screen sharing, and Time Machine.

When first reported by the same news source, build 9F32 was confirmed to pack only minor fixes, bringing the total number of code corrections to 129. None of the fixes address the Mail.app searching bug, reported as "known" in previous beta releases of OS X 10.5.5. More recently, those familiar with the progress of Mac OS X 10.5.5 were able to confirm that build 9F32 stemmed a rather serious memory glitch that was affecting Time Machine volumes formatted in HFS, while an issue when using the CUPS printing environment with documents loaded into Apple's Preview application was also acknowledged and fixed.

With these latest details revealed to the media, the seed notes for OS X 10.5.5 still list one “known issue,” particularly the one surrounding the search feature in Apple's Mail application. Noting that “only once in recent memory has the Mac maker shaved a large number of components from the focus areas of an impending Mac OS X update late in its development cycle and then spun around to re-broaden them,” AppleInsider believes OS X 10.5.5 is closer than ever to an official / public release.

The fifth maintenance and security update to Leopard, OS X 10.5.5, weighs in at 320 MB, according to testers. The final release is likely to be a bit larger in size, while the update will be made available as a free download for owners of a Mac running OS X Leopard 10.5.4 or earlier.