title: How to upgrade/downgrade subscriptions in Android InAppBilling?
body: <p>I spent a week looking for solution to upgrade/downgrade subscriptions on Android <strong>InAppBilling</strong>. </p>
  
  <p>There's a reference page about this function: <a href="http://developer.android.com/google/play/billing/billing_reference.html">http://developer.android.com/google/play/billing/billing_reference.html</a></p>
  
  <p>Google said that we could use <code>getBuyIntentToReplaceSkus()</code> method, but I couldn't found any documentation about that in its signature. I can't also see it in <strong>IInAppBillingService.aidl</strong> file that Google provided.</p>
  
  <p>Is there any one who may help me?</p>