Apple Watch and iPhone compatibility
2024/02/28 ... watchOS 10 or later. Series 9. iPhone XS or later. iOS 17 or later. watchOS 10 or later. Ultra. iPhone 8 or later. iOS 16 or later*. watchOS 9 ...
https://support.apple.com/en-us/118490
2024/02/28 ... watchOS 10 or later. Series 9. iPhone XS or later. iOS 17 or later. watchOS 10 or later. Ultra. iPhone 8 or later. iOS 16 or later*. watchOS 9 ...
https://support.apple.com/en-us/118490