
Apple today released OS X 10.11.5 to the public, marking the launch of the fifth update to the El Capitan operating system that was first released on September 30, 2015. OS X 10.11.5 comes nearly two months after the release of OS X 10.11.4, an update that introduced Live Photos for Messages and password protected notes in the Notes app.
The OS X 10.11.5 update can be downloaded through the Software Update mechanism in the Mac App Store. It is available to all OS X El Capitan users.

Most of the updates to OS X El Capitan have focused largely on under-the-hood improvements, bug fixes, and security enhancements rather than outward-facing changes, and OS X 10.11.5 is no exception. No obvious feature changes were discovered in the beta, and according to Apple's release notes, OS X 10.11.5 includes bug fixes, performance improvements, and security updates.
Prior to releasing the OS X 10.11.5 update, which has been in testing since April 6, Apple seeded four betas to developers and public beta testers.
Article Link: Apple Releases OS X 10.11.5 El Capitan With Bug Fixes and Performance Improvements