I am considering updating to an independent app for watchOS 6 (as Apple suggests) but it's not clear to me what will happen to users of older watchOS versions that have my app installed. More specifically:
What will happen if a user had the dependent app installed on their watchOS 5 watch but downloads an update of the iOS app (which now lists the watch app as independent) for their connected iOS 13 iPhone? Will the watch app be uninstalled or not function at all (since it will try watch connectivity with an iOS app that no longer supports it)?
This will definitely occur, since, according to official page:
watchOS 6 will be available for Apple Watch Series 1 and Apple Watch Series 2 later this fall.