title: Didn't find class “androidx.multidex.MultiDexApplication” on path: DexPathList on lower API <= 19 devices
body: <p>I'm trying to add Multidex <a href="https://developer.android.com/studio/build/multidex" rel="noreferrer">support</a> to my app. But I get an error:</p>
  
  <pre><code>java.lang.RuntimeException: Unable to instantiate activity ComponentInfo: java.lang.ClassNotFoundException: Didn't find class "androidx.multidex.MultiDexApplication" on path: DexPathList[[zip       file "/data/app/com.dfn.partner-2.apk"],nativeLibraryDirectories[/data/app-lib/se.android-2, /vendor/lib, /system/lib]]
  </code></pre>
  
  <p>My gradle have:</p>
  
  <pre><code>defaultConfig {
     multiDexEnabled true
  }
  </code></pre>
  
  <p>and</p>
  
  <pre><code>depenencies {
     ...
     implementation 'androidx.multidex:multidex:2.0.1'
     ...
  }
  </code></pre>
  
  <p>My AndroidManifest.xml have :</p>
  
  <pre><code>&lt;application
    android:name="androidx.multidex.MultiDexApplication"
    ... &gt;
  ...
  &lt;/application&gt;
  </code></pre>
  
  <p>What could be wrong?</p>