Apple has begun seeding its latest iOS 9.3 and OS X El Capitan 10.11.4 betas to those who are participating in its public testing program. The rollout comes just three days after Apple made these betas available to registered developers.

These are the second betas for iOS 9.3 and OS X 10.11.4, and they're very similar to the first, with almost all improvements happening under the hood. One noticeable change is a new Night Shift toggle for Control Center in iOS 9.3, which was previously spilled on Apple's website.

Both updates are available to download over-the-air for those already running beta 1. Simply visit the Software Update section in the Settings app on your iPhone, iPad, or iPod touch — or look for the update in the Mac App Store in OS X.

If you aren't already signed up to Apple's beta program and you'd like to take part, visit the Beta Software Program page by following the source link below and click the "Sign up" button. You'll need to log in with your Apple ID and follow the steps.