title: How to use different versions of the same gradle dependency in different Android Studio modules?
body: <p>In my Android Studio project, I have two modules <em>app</em> and <em>library</em>.
  Therefore I also have two <em>build.gradle</em> files.</p>
  
  <p>build.gradle(app):</p>
  
  <pre><code>dependencies {
      compile 'com.squareup.okhttp:okhttp:2.4.0'
      ...
  }
  </code></pre>
  
  <p>build.gradle(library):</p>
  
  <pre><code>    dependencies {
      compile 'com.squareup.okhttp:okhttp:2.3.0'
      ...
  }
  </code></pre>
  
  <p>When I call some retrofit methods in my <em>library</em> module, it uses okhttp 2.4.0 instead of 2.3.0. Why is this the case and how can I change this?</p>