Apple released second beta iOS 11.3 and tvOS 11.3 to public testers. Beta program members can download updates from the website Apple or 'over the air' via Settings.
iOS 11.3 will be a fairly large update with several new features and improvements. Beta 2 changes include: new explain screens App Store and iTunes Store, new Battery Health section in Settings, improved support AirPlay 2, and more.
tvOS 11.3 contains much fewer changes, but it also includes support for AirPlay 2 and other features related to iOS 11.3. Also in the update there will be automatic changes in frame rates and modes AirPlay.
Apple promises to release final versions of iOS 11.3 and tvOS 11.3 this spring.