By Sam Oliver

Published: 11:00 AM EST

Apple as early as this week could announce the release of Mac OS X 10.5.7, a seventh maintenance and security update to its Leopard operating system scheduled to deliver over a 100 minor tweaks and bug fixes.

After providing developers with weekly betas of the software for nearly two months, the Mac maker in recent days cranked up the frequency of the pre-release distributions, which is more often than not a telltale sign of an imminent release.

In particular, developers on Friday received Mac OS X 10.5.7 build 9J47, which arrived just four days after build 9J44. Late Tuesday evening developers were informed that build 9J50 was available for download, again coming just four days after the previous distribution.

People familiar with the beta test say the former build added three code-corrections to a laundry list of bug fixes, including a fix for Ethernet performance on Mac Pro systems and a correction to Mac OS X's handling of login item preferences. Meanwhile, the latter build arriving less than 24 hours ago reportedly addresses a single issue involving Bluetooth personal area networks.

Now in its seventh week of widespread testing, Mac OS X 10.5.7 includes 108 documented code corrections and is expected to arrive as an approximately 443 megabyte delta update for Mac users running Mac OS X 10.5.7. A separate distribution capable of updating earlier versions of the Leopard OS reportedly weighs in around 730 megabytes.

Further evidencing an imminent release are claims from some Apple Store customers who say Apple recently bumped up their orders for iMacs equipped with ATI's Radeon HD 4850 graphics card for shipment this week. At least one of these customers was led to believe his order was previously being held up due to the graphics card's requirement of 10.5.7, though that much is up for debate. Alternatively, Apple could include the necessary software drivers in a custom milestone of 10.5.6.

Nevertheless, it was revealed early in the beta test process that Mac OS X 10.5.7 would deliver a broad range of syncing improvements. It was later reported that the release, internally code-named Juno, would also include an updated speech dictionary.

In total, the update is expected to address issues with over 20 core system components including AirPort, graphics, iCal, iDisk Syncing, Mail, MobileMe syncing, networking, parental controls, printing, Safari, screen sharing, sound, and Time Machine. It should also improve compatibility with certain USB and Flash drives.