The sixth beta of OS X El Capitan 10.11.4 is now available for download for 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.

Apple has also released the sixth public beta version of OS X 10.11.4. Members of the Beta Software Program can download it now through the Mac App Store.

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.