title: Limit (Restrict) app installations per account (detemined by unique devices) in Android
body: <p>I have published an Android app.</p>
  
  <p>Problem is, if someone buys my app, he can install it on several devices using the same account.</p>
  
  <p>Can I limit the installation to a few (let's say 2) unique devices per account?</p>
  
  <p>If the user wants to use it on another device with the same account, he will have to uninstall from another one first.</p>
  
  <p>For example, <a href="https://play.google.com/store/apps/details?id=com.rerware.android.MyBackupPro&amp;feature=search_result#?t=W251bGwsMSwxLDEsImNvbS5yZXJ3YXJlLmFuZHJvaWQuTXlCYWNrdXBQcm8iXQ" rel="noreferrer">MyBackup Pro only allows two unique devices.</a></p>
  
  <p>How can I achieve this in my app?</p>