Among the networking changes were performance improvements to Apple File Sharing, reliability fixes for TCP connections, and both performance and reliability enhancements for AT&T Inc.-branded 3G wireless cards. Apple said it had fixed bugs in Time Machine, Leopard's integrated backup and restore application, when used with Apple's Time Capsule storage device, and in Safari.
Apple last updated Leopard in mid-September. MobileMe was also one of the target applications then, too, as it was in late October when Apple revealed it had made nearly 30 additional fixes to the sync service in a separate, behind-the-scenes update to its servers.
Mac OS X 10.5.6 can be downloaded manually from the Apple site or installed using Mac OS X's integrated update service. Also included in the upgrade are patches for 21 security vulnerabilities that address bugs in Flash Player, the operating system's kernel and its CoreTypes component.