Mac OS X version 10.5.0 "Leopard" was the sixth release of Mac OS X, Apple’s operating system for Macintosh desktop and server computers. Leopard, released on 26 October 2007 was available as an upgrade to new Apple computers purchased after 1st October 2007 that did not already have Mac OS X 10.5 installed or a Leopard upgrade DVD included. Leopard was replaced by "Snow Leopard" in late 2009. For more information about version 10.5.0, see the main article, Mac OS X 10.5.