OS X El Capitan

OS X El Capitan, or OS X 10.11, is the twelfth major release of the OS X operating system released in 2015 by Apple. It is the last version of OS X to have support for Intel processors without SSE4.1.

Features

 * New window management features were introduced.
 * Enhanced multi-touch gestures for Mail, Messages, etc.
 * Notes app received a complete overhaul.
 * Major improvements to Safari.
 * A new security mechanism called System Integrity Protection (SIP).
 * Support for the Intel Skylake processors