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 on 30 September 2015. It is the last version of OS X to have support for Intel processors without SSE4.1. It is also the last version to be released under the OS X name as the operating system was rebranded as macOS starting with the release of macOS Sierra.

Features

 * New window management features were introduced.
 * Enhanced multi-touch gestures for Mail, Messages, etc.
 * Notes app received a complete overhaul.
 * Editing extensions were introduced to the Photos app.
 * Spolight search was improved to be more contextual and now processes search queries in natural language. It can also be moved and resized across the screen.
 * Major improvements to Safari.
 * A new security mechanism called System Integrity Protection (SIP).
 * Support for the Intel Skylake processors