Apple Releases watchOS 4 With New Watch Faces, Siri Improvements, Gym Equipment Integration, and More

watchOS 4 brings more intelligence and fitness features to Apple Watch

Apple to add sleep tracking feature to Apple Watch in 2020

Apple Watch sleep tracking was planned for over five years | AppleInsider

11 Apple Watch tips and tricks

Useful Tips, Tricks, and Walkthroughs for New Apple Watch Owners