title: Android: Problems with firebase-auth and appcompat
body: <p>I'm integrating <strong>firebase</strong> to my app, but when i go to implement <code>firebase-auth:9.0.0</code> i have this error:</p>
  
  <pre><code>java.lang.IncompatibleClassChangeError: Class com.google.firebase.auth.FirebaseAuth implements non-interface class com.google.android.gms.internal.zzaja (declaration of 'com.google.firebase.auth.FirebaseAuth' appears in /data/data/com.viridesoft.kiseichuu/files/instant-run/dex/slice-com.google.firebase-firebase-auth-9.0.0_9a8a00b0dd4fa0b0760eb2c17842365e25734a0b-classes.dex)
  </code></pre>
  
  <p>I read that this error is caused by the incompatibility between <code>firebase-auth:9.0.0</code> and <code>appcompat-v7:24.1.1</code>.</p>
  
  <p>I don't know how to solve this problem.</p>
  
  <p>Edit: the problem was solved, my problem was the version of the library, i have all 9.4 but auth was 9.0</p>