title: Failed to upgrade Fabric Crashlytics to Firebase Crashlytics
body: <p>I tried to follow the officiall upgrade documentation, but after I changed every related lines in gradle files I got this error:</p>
  
  <blockquote>
    <p>A problem occurred evaluating project ':app'.
    Failed to apply plugin [id 'com.google.firebase.crashlytics']
    Could not set unknown property 'obfuscatorVersion' for object of type com.google.firebase.crashlytics.buildtools.gradle.CrashlyticsExtension.</p>
  </blockquote>
  
  <p>These are the Firebase versions:</p>
  
  <p>firebaseCrashlytics = '17.0.1'</p>
  
  <p>firebaseAnalytics = '17.4.3'</p>
  
  <p>Other related dependencies:</p>
  
  <p>classpath 'com.android.tools.build:gradle:3.6.3'</p>
  
  <p>classpath 'com.google.gms:google-services:4.3.3'        </p>
  
  <p>classpath 'com.google.firebase:firebase-crashlytics-gradle:2.1.1'</p>
  
  <p>If I comment out this line:</p>
  
  <blockquote>
    <p>apply plugin: 'com.google.firebase.crashlytics'</p>
  </blockquote>
  
  <p>everything is working fine...
  I can't upgrade to gradle 4.0.0 because DexGuard doesn't support it.</p>