The fourth beta version of OS X El Capitan 10.11.6 is now available for developers. It can be found on Apple's Developer Downloads site, or downloaded from the Updates section of the Mac App Store on a Mac running the previous beta.

Apple seeds OS X El Capitan 10.11.6 beta 4 to developers and public testers

Beta Software Program members can also get the latest update. As with the developer beta, the public beta update can be found in the Mac App Store.

OS X 10.11.6 is likely to feature a number of bug fixes and performance improvements, though Apple has not yet detailed what we'll find when it arrives for consumers.