Apple has released the first developer beta of iOS 10.3, and it comes with some important changes that you wouldn't expect from a point release.
One of the major changes is the switch to APFS or Apple File System. This was announced last year and has been in development since but is being deployed in iOS for the first time. It is Apple's new file system that will soon be available on all Apple platforms, including iOS, macOS, watchOS, and tvOS. It is built from the grounds-up for flash storage and will offer improved performance and future-proofing compared to the current HFS. This will retain your files when you update but you will not be able to go back after updating, so only update to the beta if you must and a backup is highly recommended.
The other useful addition is Find My AirPods. Clearly the paranoia surrounding losing one or both your AirPods has gotten Apple thinking hard. With this feature, you will be able to send a beeping sound through one or both your AirPods so you will be able to locate them. You can also see the last position they were in on a map before they lost connection with the phone. This will let you get close enough to them and use the previously mentioned beeping feature to narrow down your search. Assuming someone hasn't already taken off with them (not that you can do much with them without their case).
With iOS 10.3, developers will also be able to ask for ratings for their app in a new way. With the help of the new SKStoreReviewController API, developers will be able to show a dialog that will let the user rate and review the app within the app itself, without being sent to the App Store. Also, going forwards developers will be able to reply to customer reviews on the store.
Other changes include ability for developers to have multiple alternate icons for their apps, support in Siri to display Cricket scores from Indian Premier League and International Cricket Council, improved Safari 10.1, widget for Podcasts app, support for payments of bills and check status of payments in Siri with the new SiriKit, and the weather icon in Maps can be 3D Touched to show hourly forecasts and other information, among other refinements.
Along with this, Apple also released macOS 10.12.4 beta 1 to developers, which includes the Night Shift mode from iOS.