By Slash Lane

Published: 07:30 PM EST

For the second time in as many weeks, Apple has handed developers a new pre-release build of an upcoming maintenance and security release for Mac OS X 10.5 Leopard and asked that they spend the weekend testing the software.

Mac OS X 10.5.5 build 9F9 comes exactly one week after the Mac maker began widespread testing of Leopard update by privately distributed build 9F5 to its vast developer community.

Since then, the Cupertino-based company has implemented two dozen additional code corrections to bring the total number of bug fixes expected as part of Mac OS X 10.5.5 to more than 100, people familiar with the latest build say.

Among the more notable resolutions were fixes to Address Book printing, out-of-order replies and display problems with Mail app IMAP accounts, and syncing issues with both Address Book and iCal.

Those with knowledge of the ongoing beta test say Apple is also using build 9F9 to broaden developers' focus area from 18 core system components to 24. Some additions from last week's build include Directory Services, Fonts, mDNSResponder, Screen Sharing, and X11.

Unlike the previous build, however, Apple is no longer advising developers to abstain from installing the pre-release software on Macs that include integrated graphics cards.

Mac OS X 10.5.5 is presumed for a release by October, at which point it is expected to ship with support for a new generation of Macs that will include redesigned MacBook and MacBook Pro notebooks.