Following the watchOS and iOS update, Apple has also released OS X El Capitan update 10.11.5, improving the stability, compatibility, and security of the Mac, as highlighted in the release notes. The exact content of the security update is as yet unknown, as Apple has yet to update its support page detailing the fix.
Alongside the latest El Capitan comes the promised iTunes 12.4 update. The latest version of iTunes promises to bring a simpler design, easier navigation, a media picker, and more.
The update is waiting for your Mac in the App Store.