iOS 9.3 will be a bigger update than usual, introducing several new features such as Night Shift, enhancements to CarPlay, News and Health, several new education focused features for the iPad, and the ability to secure your Notes with a password or your fingerprint.
It has always been known that Apple allows employers to use its MDM deployment program to lock or track an employee's device, but the iPhone maker plans to make the program more transparent with the release of iOS 9.3. Any iPhone or iPad being tracked by an employer will soon display a message on the Lock screen that reads, "this iPhone is managed by your organization." Users with a company owned device can also navigate to Settings > General > About to see if their internet traffic is being watched and if their device can be tracked. From here you can see the name of the company tracking your device and the type of control they have over it.
Beta testing is always a risky business, especially if you are installing the unproven software on your main device. The whole point of beta testing is to identify bugs and instabilities in software that has not yet been officially released. As such, there is always the possibility of installing the software and finding that your device constantly crashes in certain situations, or certain features no longer work. For instance, the 9.3 beta has elicited complaints about Bluetooth not working properly.
Apple's Night Shift is a new feature in iOS 9.3 (which hasn't officially been released yet, but is currently available in the public beta) that is similar to the very popular f.lux app that is only available for jailbroken iPhones. The new setting lets the user shift the iPhone's display toward the warmer end of the spectrum.
Apple released its first iOS 9.3 beta to developers in mid January, and it became available to the general public shortly after. The upgrade packs quite a bit more than the typical minor release, including Night Shift which, like f.lux, shifts your display colors to the warmer end of the spectrum at night.