Sources from San Francisco stated that several other apps that have been dropped from the WatchOS include eBay, Amazon, Google Maps and Twitter. Meanwhile according to 9to5mac, "there is no mention of the Apple Watch app being pulled in the release notes which only mentions the typical bug fixes and improvements, but updating to version 39.0 on iPhone removes Instagram for Apple Watch when paired".
Meanwhile the report noted that the development was likely because of a new restriction that Apple was enforcing. The report said "As of April 1, updates to Apple Watch apps must use the WatchOS 2 SDK or later, while new Watch apps have to be built with the WatchOS 4 SDK”, which means that Apple have stopped accepting updates to non-native WatchOS apps, so Instagram either had to rework the software or drop it altogether.
Moreover the company reportedly chose to drop it and
the fact that the app was non-native means that it could neither make use of
Wi-Fi and LTE nor could it play videos. Engadget reported that Apple might
introduce a way for third-party apps to make use of LTE and after this support,
Instagram might reappear on WatchOS.
