Add Device group management

[DamienDoumer]

Firebase permits users to manage devices via Device group messaging. This can be very useful for developers willing to build a backend that sends notifications to users with multiple mobile devices. Here is what we can do with device group messaging via HTTP calls. Having a C# dotnet implementation will be very useful.

I made a little library that leverages the firebase admin sdk for dotnet and implements device group messaging in it. You can find it here, could my work be integrated into this library? Implementing this feature doesn't seem very difficult, so I'm wondering, Is there a reason why device group messaging is not available in the admin SDK ?

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[chong-shao]

Group feature is going to be replaced by the topics feature hence we decided to not support group management in Admin SDK.

More context can be found in https://github.com/firebase/firebase-admin-node/issues/173

[DamienDoumer]

@chong-shao thanks for the info. Please, how can we keep ourselves aware of when the new Topics feature will be available? That is, receive any update about its availability?

[chong-shao]

Hi @DamienDoumer, we don't have a specific timeline for that for now. A newly launched feature will be mentioned in FCM API documentation https://firebase.google.com/docs/cloud-messaging/send-message and Admin SDK release notes.

[DamienDoumer]

Ok, noted.

[indorock]

What a weird decision, especially considering the actual docs literally recommend us to NOT use Topics and only use device groups when sending to multiple devices for a user.