title: Is there a way to implement the "expiration" time in a Firebase notification sent from php server?
body: <p>I've implemented a php server that send Firebase Notification to users that are subscribed to a specific topic of my Firebase project.</p>
  
  <p>It works.</p>
  
  <p>In the console of Firebase there is the possibility to set the "expiring time" of the notification (from 1 minute up to 4 weeks).</p>
  
  <p>Is there a method to insert this possibility also in my php server?</p>
  
  <p>Thank you</p>