OS X Mavericks

OS X 10.9 "Mavericks" is an operating system made by Apple Inc. for its Macintosh line of computers. It is a version of OS X, and carries the release number 10.9. It was released on October 22, 2013. According to Apple, "Mavericks" contains over 200 changes and improvements since OS X Mountain Lion.
OS X Mavericks was the first OS X major release to be a free upgrade since Mac OS X 10.1 "Puma".