Face detection which allows for adjusting the detail in faces
Support for iCloud Photo Library and Photo Streams
Optimized for iOS 9 and iPad Pro
3D Touch Quick Actions and Peek and Pop photo previews for the iPhone 6S and 6S Plus
TIFF file format option added (enable in settings)
Here's a quick sample to show the difference in an image with no face detection (left) and 100% face detection (right).