"Hey Siri" support and possibly wireless charging case alongside AirPower charging mat.
Apple Seeds Sixth OS X 10.11 El Capitan Beta to Developers
The update, which arrives as Build 15A244d, is available through the software update mechanism in the Mac App Store and through the Apple Developer Center.
While early betas introduced minor design changes and features, the last few betas have focused on under-the-hood performance improvements and bug fixes to optimize OS X El Capitan ahead of its public release.
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.