I am trying to implement server for FCM to send notifications to android/iOS devices.
I need to send data-only notifications to both android and iOS but iOS seems very unstable for background notifications. (even though the app is in foreground, I often not get message at all.)
When I test with legacy FCM REST server with FCM direct channel, it works great on iOS but this is not an option for me as newer Admin SDK doesn't support direct channel.
Is there any reason to remove support for FCM direct channel in newer Admin SDK? I see all Firebase docs recommend to use Admin SDK but not sure why they removed the support for direct channel.