On April 10, 2018, Google deprecated GCM. The GCM server and client APIs were removed on May 29, 2019, and currently, any calls to those APIs can be expected to fail.
In reference to the same Punchh has already Migrate GCM apps to Firebase Cloud Messaging (FCM), which inherits the reliable and scalable GCM infrastructure, plus many new features.
For more information, you can check https://developers.google.com/cloud-messaging/faq
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