 Because of Cairo's lack of support for Windows 95, Windows 98, Windows ME, and Windows NT (versions 4.0 and below), and because Microsoft ended support for Windows 98 and Windows ME on July 11, 2006, Firefox 3 does not run on those operating systems.Similarly, the Mac version of Firefox 3 runs only on Mac OS X 10.4 or higher, but, unlike previous versions, has a native Cocoa widget interface.As for the frontend changes, Firefox features a redesigned download manager with built-in search and the ability to resume downloads.