title: Gradle sync failed: Version: 8.4.0 is lower than the minimum version (9.0.0) required for google-services plugin
body: <p>I'm trying to integrate Google's Firebase SDK as explained <a href="https://firebase.google.com/docs/android/setup">here</a></p>
  
  <p>But I'm getting this error when I try to build the project:</p>
  
  <p><code>Gradle sync failed: Version: 8.4.0 is lower than the minimum version (9.0.0) required for google-services plugin.</code></p>
  
  <p>This is my project's <code>build.gradle</code> file :</p>
  
  <pre><code>buildscript {
      repositories {
          jcenter()
      }
      dependencies {
          classpath 'com.android.tools.build:gradle:2.1.0'
          classpath 'com.google.gms:google-services:3.0.0'
      }
  }
  
  allprojects {
      repositories {
          jcenter()
      }
  }
  </code></pre>
  
  <p>and this is app's <code>build.gradle</code> file:</p>
  
  <pre><code>buildscript {
      repositories {
          maven { url 'https://maven.fabric.io/public' }
      }
      dependencies {
          classpath 'io.fabric.tools:gradle:1.+'
      }
  }
  apply plugin: 'com.android.application'
  apply plugin: 'io.fabric'
  
  repositories {
      maven { url 'https://maven.fabric.io/public' }
  }
  android {
      lintOptions {
          abortOnError false
      }
      signingConfigs {
          release {
          }
      }
      compileSdkVersion Integer.parseInt(project.COMPILE_SDK_VERSION)
      buildToolsVersion project.BUILD_TOOLS_VERSION
      defaultConfig {
          applicationId 'club.androidy.callcontrolfree'
          minSdkVersion project.MIN_SDK
          targetSdkVersion project.TARGET_SDK_VERSION
          versionName project.VERSION_NAME
          versionCode Integer.parseInt(project.VERSION_CODE)
      }
      buildTypes {
          release {
              minifyEnabled true
              proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.txt'
              signingConfig signingConfigs.release
          }
      }
      productFlavors {
      }
  }
  
  dependencies {
      compile fileTree(include: ['*.jar'], dir: 'libs')
      compile 'com.google.android.gms:play-services-ads:8.4.0'
      compile 'com.google.android.gms:play-services-analytics:8.4.0'
      compile 'com.android.support:support-v4:23.3.0'
      compile 'com.android.support:design:23.3.0'
      compile('com.crashlytics.sdk.android:crashlytics:2.5.5@aar') {
          transitive = true;
      }
      compile 'com.android.support:cardview-v7:23.3.0'
      compile 'com.google.firebase:firebase-core:9.0.0'
      compile 'com.google.firebase:firebase-crash:9.0.0'
  }
  apply plugin: 'com.google.gms.google-services'
  </code></pre>
  
  <p>What's wrong here?</p>
  
  <p>Thanks in advance.</p>