Mac OS X Leopard

Mac OS X Leopard (10.5) was released in October of 2007. Leopard was supposed to release in 2006, but it was delayed due to the launch of the iPhone. It is the first version of Mac OS X to drop support for G3 systems and introduces a new version of Aqua that Apple would use until Snow Leopard. The Universal Binary concept was extended in Leopard, as the separate builds for Intel and PowerPC Macs were unified in Leopard and installation media could be used for either system. The first 64-bit Mac applications were designed for Leopard due to a new 64-bit userland (the kernel remained 32-bit until Snow Leopard).

Features

 * New unified UI with an iTunes-like design
 * Core Animation - An API allowing for keyframe animation in the OS X UI
 * 64-bit userland and system libraries
 * 3D Dock with support for Stacks
 * Spaces - a multi-workspace manager
 * Time Machine - a backup utility
 * Safari 3 with support for WebClips
 * Updated Finder with multithread support
 * Quick Look - Allows previewing files in Finder without launching an app