Apple makes OS X 10.11.4 Beta 1 available to developers and public tests. The Build number of this version is 15E27e.

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The update of OS X 10.11.4 Captain has improved stability, compatibility and security for your Mac.

Developers can [Download] iOS 9.3 Beta 1 at the Apple developer site. If you want to be a public tester sign up on the [Beta site].