Apple released Mac OS X 10.5.4 today, a bug-fix update that touches on several areas. Recent security updates are included (though the recent ARDAgent vulnerability has not yet been addressed; see "How to Protect Yourself from the New Mac OS X Trojans," 2008-06-25). If you want to take advantage of the security updates without installing the operating system update, you can download Security Update 2008-004 for Intel (128 MB) and PowerPC (80 MB); security updates for Mac OS X 10.5 Server are also available for Intel (165 MB) and PowerPC (127 MB).

Designers will be relieved to discover that a problem with saving and reopening Adobe Creative Suite 3 files located on remote servers has been resolved. A pair of AirPort fixes deal with reliability of 5 GHz networks and poor performance when using Logic Studio or MainStage.

According to Apple's release notes, iCal sees the most improvements, such as resolving problems when deleting events, copying and pasting attendees between events, and reliability of shared meetings. Fixes in Safari center on improving performance and solving problems loading secure Web pages. Apple is still grappling with the way Spaces operates, fixing a problem where the Finder would become the active application when switching to a space instead of the program residing in that space, as well as an issue dealing with assigning applications to spaces in the Spaces preference pane.

This update also includes a number of new security fixes, including major updates to patch recent vulnerabilities discovered in the Ruby programming language. Two fixes close holes that could allow an attacker to take over your computer if you were to visit a malicious Web site using Safari. One of those vulnerabilities is exploitable only if you have the Safari preference to "Open 'safe' files after downloading" set - this is a valuable reminder to disable that preference in Safari's General preference pane.

The Mac OS X 10.5.4 update also adds raw format support for more cameras, fixes a problem where X11 may not be completely installed, and improves L2TP VPN client reliability.

The update is available via Software Update or as standalone downloads: Mac OS X 10.5.4 Update (88 MB); Mac OS X 10.5.4 Combo Update (561 MB); Mac OS X Server 10.5.4 Update (133 MB); Mac OS X Server Combo 10.5.4 Update (677 MB).