How to send FCM Push Notifications from one device to another using Http v1 Oauth2 access tokens on Android API 19 (less than API 26 generally)?
I’m working on an android project where I’ve to use FCM push notifications. Since legacy API is going to be removed in the coming days, I used FCM with Http v1 Oauth2 Access Tokens. It worked correctly to send a notification from Android 12 (API 32), but not from Android 4.4 (API 19). Both are physical devices. API 19 device received it successfully when the other device sent it, so FirebaseMessagingService is definitely working on it. The only problem is to send a notification from API 19 (and potentially all devices under API 26).