Which watchOS does Phaze require?

Phaze on Apple Watch requires watchOS 10 or later, paired with an iPhone running iOS 17 or later. The watchOS 10 baseline is what enables the SwiftUI APIs Phaze uses for the Digital Crown weight entry, the live fasting timer activity, the four complication sizes, and the HealthKit reads and writes that let the watch act independently from your phone. If your Apple Watch is on an older version, the watch app simply will not appear in your Watch app list, but you will still get the full iPhone app. Most Apple Watch Series 5 and later models can run watchOS 10. Update from the Watch app on iPhone, General, Software Update, and Phaze for Watch will install over the air automatically.