Apple has released the fourth beta of OS X El Capitan 10.11.4 to developers. It can be found now at the Mac Developer Resource Center, or in the Updates section of the Mac App Store on a machine with the previous beta installed.

The changes that OS X 10.11.4 will bring when it launches publicly have not yet been announced, though it's likely to contain a number of performance improvements and bug fixes. While this is currently a developer-only beta, members of the Beta Software Program should be on the lookout for a public beta version to hit soon.