Apple today seeded the fourth beta of an upcoming iOS 9.3 update to developers for testing purposes, two weeks after seeding the third iOS 9.3 beta and more than two months after the public release of iOS 9.2, the last major update to iOS 9. iOS 9.3 has been in testing since January 11.

The fourth iOS 9.3 beta is available as an over-the-air update and through the iOS section of the Apple Developer Center.

As a major .1 update to the iOS 9 operating system, iOS 9.3 introduces several new features. There's a Night Shift mode to reduce the amount of blue light iOS users are exposed to in the evening by shifting the iPad or iPhone display to a warmer (yellower) color spectrum, and there are several features designed to improve the iPad for Education program, such as multi-user login. Multi-user login, while an appealing feature, is limited to MDM customers and is not available to the general public.

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Multiple apps and features are also seeing updates in iOS 9.3. Apple News includes more personalized recommendations, faster updates, a landscape view on the iPhone, and support for in-line video, while Health includes a new Apple Watch-style "Activity" view, Notes has an option to password protect individual entries, and third-party apps can add songs to Apple Music.

Apple Music for CarPlay offers "New" and "For You" sections for better music discovery, and a Nearby Feature in CarPlay Maps offers more information about what's close by. Paired with watchOS 2.2, an iPhone running iOS 9.3 is able to support multiple Apple Watches, and for iPhone 6s users, there are new Quick Actions for Weather, Settings, Compass, Health, App Store, and iTunes Store.

The second iOS 9.3 beta added a Control Center toggle for the Night Shift feature, while the third iOS 9.3 beta focused on fixing bugs and added Verizon Wi-Fi calling. New features found in the fourth beta will be listed below.

What's new in iOS 9.3 beta 4:

Night Shift - The Control Center icon for Night Shift has been redesigned. It's now a moon inside of a sun instead of a moon inside of an eye.