First the short version: has anyone managed to get push notifications from Salesforce working with an Android app, since Google moved Google Cloud Messaging into Firebase Cloud Messaging?
A friend of mine is working on a mobile app - he's more of a mobile dev than Salesforce dev, but is making headway with the Mobile SDK.
One area he's hit a roadblock with is push notifications. The Mobile SDK developer guides are a little out of date in this area, as they talk about setting up Google Cloud Messaging, however, Google rolled this into Firebase Cloud Messaging. From what I can tell they worked hard to make sure nobody would be affected, and the old endpoints should work with the same methods and payloads.
Whether we use the Send Test Notification page, or try to use the PushNotification classes, we get no errors (the Send Test Notification even says it worked), but we don't get a message delivered to the device either.
If we fire up POSTman and hit Firebase directly, the messages are received by the app, so I think that rules out the Firebase-to-app part. The only other area is the Salesforce to Firebase part.
I'm wondering if there's something ever so slightly, subtly changed in the move to Firebase that's causing an issue with Salesforce calling GCM/FCM. It seems unlikely given the change happened last year, but I'm running out of ideas...
So to return to the original question: has anyone got push notifications working with an app that's solely in Firebase, and not GCM? If so, any tricks or tips that you have to share?
Alternatively, is there still a way to create GCM apps that I'm not aware of? That might be worth a shot if there is.