Apple has released watchOS 9 release candidate to developers for testing. The build number is 20R361.
watchOS 9 brings great new ways to keep you active, healthy, and connected with Apple Watch. You have more ways to train and measure your workouts, a completely redesigned compass app, a new app to track your medications, more powerful sleep tracking with sleep stages, and better insights and support for your heart health if you have been diagnosed with atrial fibrillation.