Batch is fully compatible with FCM from the 1.12 version of the SDK.

While new integrations will automatically use it, applications that already used Batch require some changes to explicitly opt-in to an FCM migration. We strongly recommend that you update your app as soon as possible.

You will find all the information you need to migrate to FCM here, in the documentation:

Once you've done this, the log with your registration ID should change, and say that it is using FCM:

If you see GCM instead of FCM or an error, please try to follow the documentation again, or contact us.

Then, try to send a test notification to your device using that token. If you see a "mismatch sender ID" error, you probably didn't migrate your old GCM project to Firebase and used a different Firebase project instead. Follow this step-by-step guide to fix the issue: Fix a mismatch between push tokens and your Sender ID.