With every release Android makes it harder to have a service running in the background. With the introduction of doze there is no alternative to using FCM. FCM

With every release Android makes it harder to have a service running in the background. With the introduction of doze there is no alternative to using FCM. FCM has a privileged service where it is able to wake up the device from doze. A custom push service will never be able to do this. There might be hacks, but I'd rather take Googles approach than to work around on each and every release.