Apple has released its first major update to iOS 10 after releasing several minor updates with bug fixes. iOS 10.1 is mostly about the iPhone 7 Plus and its Portrait Camera mode. The new Portrait mode allows iPhone 7 Plus users to utilize the device's wide-angle and telephoto lenses to create a "bokeh" effect, or blurred backgrounds.
The update includes new Maps features, various bug fixes, and the ability to replay Message effects. Apple has also added an option to utilize Message effects when the Reduce Motion is enabled. You can achieve this by activating the Auto-play Message Effects slider in Settings -> General -> Accessibility -> Reduce Motion.