Apple has released the latest version of Leopard, with bug fixes and security updates accompanying the fifth update to the operating system. The fixes include improvements to MacBook Air performance, iPhone and PalmOS synching, Time Machine and Time Capsule reliability, Mail IMAP and SMTP compatibility, and tweaks to iCal and Address Book. The update also improves MobileMe syncing, Disk Utility, Speech Dictionary, and Kerberos authentication with some Samba servers. Apple claims that there are extensive graphics fixes, though no details are given as to what that might mean.
The Mac OS X 10.5.5 Update is recommended for Mac OS X Leopard versions 10.5, 10.5.1, 10.5.2, 10.5.3 and 10.5.4. It includes general operating system improvements that enhance the stability, compatibility, and security of your Mac.
Source
