Three million downloads of Mountain Lion have been clocked since it’s availability four days ago, making it the most successful OS X release ever, say Apple.

It is the ninth major release of the Mac operating system, and is available as an upgrade for £13.99. 

“Just a year after the incredibly successful introduction of Lion, customers have downloaded Mountain Lion over three million times in just four days, making it our most successful release ever,” said Philip Schiller, Apple’s senior vice president of Worldwide Marketing. 

Mountain Lion has a number of new features, including a Messages app, Notification Center, system-wide Sharing, better Facebook integration, Dictation, AirPlay Mirroring and Game Center.