Apple today has released the fourth developer preview of OS X 10.11 El Capitan. The operating system carries the build number 15A226f. Two weeks ago, the company pushed the third beta build to developers after initially introducing the operating system at WWDC last month. Beta 3 brought about a variety of minor changes, including changes to Mission Control, the Photos app, and the Calendar app.
Read more at http://9to5mac.com/#M56Y4r7mWYzCP6Hr.99
Update is available – release notes will become available here