OS X El Capitan ( el KAP-i-TAHN) (version 10.11) is the twelfth major release of macOS (named OS X at the time of El Capitan's release), Apple Inc.'s desktop and server operating system for Macintosh. It focuses mainly on performance, stability, and security. Following the California location-based naming scheme introduced with OS X Mavericks, El Capitan was named after the famous eponymous rock formation in Yosemite National Park. El Capitan is the final version to be released under the name OS X. OS X El Capitan received far better reviews than Yosemite.
The first beta of OS X El Capitan was released to developers shortly following the WWDC keynote on June 8, 2015. The first public beta was made available on July 9, 2015. There were multiple betas released after the keynote. OS X El Capitan was released to end users on September 30, 2015, as a free upgrade through the Mac App Store.
OS X El Capitan is the final version of OS X to support aluminum Macs and Xserve, as its successor macOS Sierra is incompatible with the mid-2007 and final models of these products.