Apple has begun the third maintenance and security update to the Leopard operating system, issuing a "pre-release copy of the software update featuring a focus list spanning some two dozen core components," according to AppleInsider.. Build 9D10 addresses the most important pieces that make up Leopard.

AddressBook, AppleScript, Audio, Back To My Mac, Dashboard, the Dock, DVD Player, Finder, Graphics, iCal, Mail, Portable Home Directories, Printing, Rosetta, Spaces, Spotlight, Time Machine, and VoiceOver are just some of the components that need evaluation, according to the news source.

Also, Dashboard, iCal alarms and syncing, Installer App, Spotlight indexing, PDFs within the Preview App, Mail alarms, Spaces, Stacks and the Dock are in for a major pest control. Memory leaks in CoreAnimation and iCal are also being dealt with.

Needless to say, Mac OS X 10.5.3 is just a maintenance update, but quite a big one at that. New features are yet to be disclosed, regarding the components mentioned above, but as we all know, Apple will probably wait until the last five minutes prior to its release in order to disclose all the details.

The fact that Apple trusted Mac OS X Leopard 10.5.3 beta with developers means that it is quite stable and should hit macs within weeks. Sources estimate an April, May (the latest) release for the final version.

Mac OS X version 10.5, Leopard, is the sixth major release of the Mac OS X operating system for line of personal computers. It is the successor to Mac OS X v10.4, aka, Tiger, packing over 300 changes and enhancements, covering core operating system components, as well as included applications and developer tools.

Leopard is available in two variants: a desktop version for personal computers, and a server version (Mac OS X Server).