title: Upgrading Gradle version in legacy android application
body: <p>I am currently working on a legacy android project which had Google Analytics implementation since last three years .
  Recently there is need of implementing Android Firebase in the same project as Google will be discontinuing GoogleAnalytics.
  When I tried to integrate Firebase to my application, I got error while building application that I am running on Gradle version 2+ and to support firebase Application needs to be upgraded to Gradle version 3+.
  Application also has couple of legacy libraries also , which also needs some modifications.
  Current Gradle  version is 3.4.1, when I am trying to upgrade gradle version I am facing lots of dependacies issues and Older classes needs to be removed for eg. ActionBarActivity which is removed from Android SDK.</p>
  
  <p>What should be the approach in this scenario as I am getting lint issues while building project.
  Is there any safe way to upgrade gradle system?</p>
  
  <p>I have tried upgrading gradle file to version 3.4.1 and <code>gradle.properties</code> to version 5.1.1 </p>
  
  <pre><code>distributionUrl=https\://services.gradle.org/distributions/gradle-5.1.1-all.zip
  </code></pre>
  
  <p>It would be ideal if I am able to update my project to the latest gradle version so that application will be compatiable to the latest Ansroid OS</p>