iOS 10 How to set UNotificationContent threadIdentifier for remote notification
TL;DR: What key needs to be set in the APNs notification payload JSON to correspond to the threadIdentifier property of the UNNotificationContent object? e.g. the "category" key corresponds to the categoryIdentifier property. iOS 10 introduces the Notification Content Extension allowing us to present a view controller when a notification is expanded. The view controller that we provide conforms to the UNNotificationContentExtension protocol, that requires us to implement the didReceive(_:) method. The documentation for this method includes the following paragraph: This method may be called