There is a relationship between the iOS version you're supporting on a phone, and watchOS version available for a paired watch. For example, watchOS 2.1 would not be available with a phone running 9.0.x or 9.1
If you are supporting less recent versions of iOS, please set your minimum watchOS version to 2.0.
You can find this in Project Settings -> Watch App Target -> Build Settings -> (null) - Deployment -> watchOS Deployment Target:
