Apple has updated client and server editions of Mac OS X 10.5 Leopard, with an update of improvements and tweaks.

Apple's notes accompanying the 110MB software download (for client Macs here, for Mac servers here) say the update addresses issues with Airport, Back to My Mac, Disk utilities, iCal, Mail, Networking, Printing, Security and Firewall, System and Finder, and Time Machine.

Mac OS X 10.5.1 has a host of tweaks to the OS. Highlights include an improvement in the reliability of Back to My Mac-enabled Macs appearing in the Finder's Shared Sidebar.

Leopard critics will be most pleased with an improvement to Leopard's built-in firewall. In Security preferences' Firewall tab, the 'Block All' option is now called 'Allow Only essential services". Many users had expressed confusion at the new naming conventions and internet boards have been buzzing with bafflement over the machinations of Leopard's firewall since the OS shipped.

AirPort users should now see password-protected accounts on AirPort Disks show up in the Finder's Shared sidebar, while the update also resolves an issue with saved passwords for wireless networks.

Disk Utility is also more stable than before, offering better disk partitioning when setting up RAID systems and restoring progress bar functionality.

Mail sees improved stability when resizing columns in the message viewer or switching between Stationery templates in email messages. The update also addresses a problem in which attachments enclosed inside an HTML link may not be clickable in messages. Simple Set-up and Smart Mailbox/.Mac sync compatibility have also been improved.

System/Finder improvements include better compatibility with Adobe Flash-based uploaders in .Mac Web Gallery, better text drawing when visiting Adobe Flash-based websites and an end to potential data loss when moving files across partitions in the Finder.

The Leopard Server update also delivers improvements within Server Preferences, NetBoot, Open Directory and SMB File Service.