Theater Mode, if what rumors have to say go right, will provide one-button option to manage contrast, brightness, audio, and notifications. Thus, while watching a movie or show, you can check social status, message someone, check email and do more without causing disturbance to who is sitting next to you.
Improved Apple Pencil:
With iOS 10.3 updates, Apple Pencil is expected to go more sensitive, responsive and helpful than ever before. Apple Pencil is nothing but a replica of a regular pencil or pen. It allows users to draw images or write on their iPad Pro device manually as they do with a pencil or pen on paper.
Apple Pencil has sensors that communicate with the application running on iPad. Sensors emit signals towards the iPad screen with frequency as high as 240 times per second for a lag-free writing or drawing experience. With a bid to give it an edge, Apple is also likely to introduce the new edition of iPad Pro around March or April with better hardware capabilities that can sense pressure, orientation and angle of Apple Pencil in a much better way.
Courtesy : https://www.rootinfosol.com/new-ios-10-3-features-to-add-more-to-user-experience-2017