By Slash Lane

Published: 01:00 PM EST (10:00 AM PST)

Apple this month is simultaneously putting the final touches on a pair critical operating system updates -- one that will close out an era in Mac computing and a second that will signify fresh beginnings.

Mac OS X 10.4.11

Expected to be released first is Mac OS X 10.4.11, which is likely to stand as the Tiger operating system's final curtain call. Apple earlier this week provided its developer community with two new pre-release builds of the software labeled Mac OS X 10.4.11 build 8S155 (for PowerPC Macs) and Mac OS X 10.4.11 build 8S2155 (for Intel Macs).

Adding to the three-dozen fixes already built into previous seeds, the new builds include a handful of fresh code corrections, the most significant of which addresses an image syncing bug with iPhones that contain large photo albums.

Among the other system components that have already seen improvements via previous builds are: WebCore, SearchKit, BlueTooth (enabling/disabling), Networking and Cisco VPN, Directory Services, CoreAudio and m4a files, File Manager and POSIX volumes, and CoreAudio and decoding iTunes Plus files.

Mac OS X 10.5

Meanwhile, Apple is also inching closer to unleashing its next-generation Mac OS X 10.5 Leopard operating system, due on the market by the end of October.

Following a month-long dry spell in software's seeding process, the Cupertino-based firm this week issued two small updates to developers running the most recent builds (9A527 (client) 9A528 (server)) of Leopard.

Both updates arrived via Software Update, with the first being a new version of the Software Update mechanism in itself. Apple has historically tested Software Update's ability to download and update to a new version of itself when a system update is nearing release.

After applying that update, developers gained access to download Mac OS X 10.5 Leopard build 9A528d, which includes bug fixes and is also intended to verify the that the new version of Software Update functions properly.