Previewed at WWDC, launching in the fall.
Apple Seeds Fourth OS X 10.11 El Capitan Beta to Developers
The update is available through the software update mechanism in the Mac App Store and through the Apple Developer Center.
It is not clear what today's update adds to the operating system, but we will add any new features and bug fixes to this post as they're discovered. Previous betas have featured primarily under-the-hood fixes to improve performance and reliability.
OS X El Capitan builds on the features introduced with OS X Yosemite, focusing on improving performance and user experience. Behind-the-scenes improvements in El Capitan have made a number of apps and processes on the Mac much faster, and the introduction of Metal makes system-level graphics rendering 40 percent more efficient.
Along with a new systemwide font, El Capitan includes a revamped Mission Control feature, a new Split View feature for using two full-screen apps at once, deeper functionality for Spotlight, and several new features for Safari, including Pinned Sites for housing frequently visited websites and a universal mute button that quiets all tabs.
OS X 10.11 El Capitan is available to both registered developers and public beta testers. After testing is completed, Apple will release El Capitan to the public in the fall.