Apple today released the eighth beta of OS X El Capitan to developers for testing purposes, nearly two weeks after releasing the seventh El Capitan beta and more than two months after unveiling the operating system at its 2015 Worldwide Developers Conference.

Today's update, build 15A279b, is available through the software update mechanism in the Mac App Store and through the Apple Developer Center. There's also a new sixth beta for public beta testers, which is identical to the eighth developer beta.

It is not clear if this update will add any outward-facing changes to El Capitan, as many of the prior betas have focused on under-the-hood performance improvements and bug fixes to optimize the operating system ahead of its public release, but beta 7 did add some minor cosmetic updates to El Capitan.

As an update complementary to OS X Yosemite, OS X El Capitan builds on the myriad features introduced last year. Behind-the-scenes improvements in El Capitan make a number of apps and processes on the Mac faster, and the introduction of Metal makes system-level graphics rendering 40 percent more efficient.

El Capitan introduces a new system-wide font, a revamped Mission Control feature, a split-view feature for using two full-screen apps at once, deeper functionality for Spotlight, and improvements to Safari that include Pinned Sites and a universal mute button.

OS X 10.11 El Capitan is currently available to both registered developers and public beta testers. Apple plans to release El Capitan to the public in the fall.