Twelfth major release of OS X (10.11)
OS X El Capitan is the twelfth major release of OS X, Apple Inc.'s desktop and server operating system for Macintosh computers. It is the successor to OS X 10.10 Yosemite. The first beta of OS X El Capitan was released to developers shortly following the 2015 WWDC keynote. OS X El Capitan is an update that focuses mainly on performance, stability, and security.