Apple today is rolling out the third beta of watchOS 4 to developer. The rollout comes following the release of the third betas of macOS High Sierra, tvOS 11, and iOS 11 earlier this week. The update carries the build number 15R5321h.

watchOS 4 includes changes such as interface tweaks, app list navigation, and more. We’ve gone in-depth with over 50 of the changes watchOS 4 brings. Read our past coverage of the update at the links below:

  • What’s new in watchOS 4? Hands-on with 50+ features and changes [Video]
  • Health in iOS 11 & watchOS 4: Diabetes management, insulin delivery, CoreBluetooth, new Workout data & more
  • How to switch between list view and honeycomb app grid on Apple Watch with watchOS 4
  • You’ll probably need to upgrade your iPhone 5 or 5c to update Apple Watch to watchOS 4

Of note, you should be particularly cautious when installing the watchOS 4 beta as there is no way to revert to the more stable watchOS 3 in case of problems. Nevertheless, the update is available in the Apple Watch app on iPhone for developers.