Today Apple released its third beta iOS 11.2, watchOS 4.2, macOS High Sierra 10.13.2, and tvOS 11.2 to registered developers and beta program members. The corresponding public beta versions should be out soon.
iOS 11.2 beta 3 (build number 15C5107a) can be installed on iPhone, iPad or an iPod touch with a previous beta version and a suitable profile (which can be downloaded from the website Dev Center). This is done 'over the air' through the Software Update mechanism in Settings.
The second beta version iOS 11.2 was released last week and has the Apple Pay Cash feature.
Apple Pay Cash is also supported in watchOS 4.2.
In addition, iOS 11.2 will support Siri Kit for HomePod, AirPlay 2 and paid trial app subscriptions iOS and macOS.
Developers will be able to charge a partial price for an auto-renewing trial subscription for their app at App Store. They will be able to add the price to the iTunes Connect page soon.
Messages in iCloud never appeared in iOS 11.2 beta 3.
watchOS 4.2 beta 3 (build number 15S5100a) can be downloaded and installed via the associated app on the linked iPhone. The watch must be at least 50% charged and connected to a charger.
tvOS 11 beta 3 (build number 15K5099a) is available for Apple TV 4th generation and Apple TV 4K. You can download the update in Settings. Your Apple TV should also have a suitable profile.
tvOS 11.2 is a bug fix update with only new features to automatically adjust the frame rate and dynamic range for 4K and HDR content to Apple TV 4K.
Also added was automatic region selection during setup, switching between 50Hz and 60Hz, as well as the Unviewed category in TV shows, movies and home videos.