The Mac OS X 10.5.4 Update is recommended for Mac OS X 10.5, 10.5.1, 10.5.2, and 10.5.3 Leopard. It includes general operating system improvements that enhance the stability, compatibility, and security of your Mac.
The update is available, as usual, via Software Update under the Apple menu. Also, to be ultra-cautios, you are recommended to back up your system before applying the update.
A standalone installer is also available from Apple Support Downloads. There are two different updaters if you take this route (Software Update automatically checks which version you need).
• The delta update lets you update from Mac OS X 10.5.3 to 10.5.4
• The combo update lets you update from Mac OS X 10.5, 10.5.1, 10.5.2, or 10.5.3 to 10.5.4
• Includes recent Apple security updates.
• Resolves an issue with saving and reopening Adobe Creative Suite 3 ﬁles on a remote server.
• Includes additional RAW image support for several cameras.
• Addresses an issue that may result in a partially installed X11 application.
• Improves L2TP VPN client reliability.
• Addresses AirPort reliability issues with 5GHz networks.
• Addresses AirPort issues that may result in slower performance in Logic Studio or MainStage.
• Improves overall iCal reliability for meeting requests, cancellation notices, delegation, and syncing with iPhone.
• Resolves an issue that prevents deleting an iCal event without notifying the creator.
• Addresses an issue in which events in all calendars affect availability. A checkbox now enables information-only calendars to be transparent from free/busy lookups.
• Resolves a UI issue preventing delegated calendars from showing up as a separate window.
• Addresses an issue with copying and pasting attendees from one event to another.
• Resolves an issue in which iCal may not delete events after a speciﬁed time interval, even when set to do so in iCal preferences.
• Addresses an issue in which To Dos cannot be marked private.
• Addresses a potential performance issue when loading secure web pages.
• Resolves issues that may be encountered when accessing secure web pages with client certificates that reside on a smart card.
Spaces and Exposé
• Addresses an issue in which switching from a space with a Finder window keeps the Finder as the active application instead of the application residing in the destination space.
• Fixes an issue in which dragging an application from the list of application assignments in Spaces System Preferences does not assign the application to the desired space.
• Resolves an Exposé issue that may result in only a subset of windows being shown.
For information about security updates, please see this article.