FCMPlugin.gradle

// This is a working .gradle file for cordova-plugin-fcm-with-updated plugin, 
// to use with cordova-android 6.3.0

def FCM_CORE_VERSION = System.getenv("FCM_CORE_VERSION") ?: '16.0.9'
def FCM_VERSION = System.getenv("FCM_VERSION") ?: '18.0.0'

buildscript {
    repositories {
        mavenCentral()
        jcenter()
        mavenLocal()
        // google()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:2.3.+'
        // classpath 'com.android.tools.build:gradle:3.4.1'
        /**
         * Reference: https://github.com/google/play-services-plugins/issues/22
         *
         * PS: 4.2.0 throws a NullPointerException when use gradle plugin
         *     com.google.gms.googleservices.GoogleServicesPlugin class reference
         *     instead of id(string)
         */

        // classpath 'com.google.gms:google-services:4.1.0'
        classpath 'com.google.gms:google-services:3.0.0'
    }
}
repositories {
    mavenCentral()
    jcenter()
    // google()
}
dependencies {
    compile "com.google.firebase:firebase-core:${FCM_CORE_VERSION}"
    compile "com.google.firebase:firebase-messaging:${FCM_VERSION}"
}
// apply plugin: 'com.google.gms.google-services'
// class must be used instead of id(string) to be able to apply plugin from non-root gradle file
apply plugin: com.google.gms.googleservices.GoogleServicesPlugin