Apple just rolled out the latest public beta for its upcoming OS X El Capitan release. You can grab beta 4 now from the Mac App Store, assuming you’re signed up for the company’s public beta tester program.

Apple released a third public build just last week in an effort to improve performance and squash a few bugs, and beta 4 seems just as minor. 9to5Mac noted a new blue wallpaper and a tweaked General icon. This is the same as the new developer beta that was released on Monday (build 15A244d), which includes additional evidence that a 4K 21.5-inch Retina iMac is on the way.

El Capitan will be available for free later this fall. It includes some large improvements including an improved Safari browser, Spotlight search, and Mission Control. It also brings Metal to the Mac and adds the ability to quickly find the cursor by shaking your mouse.