Remove already sent push notification from server

Question

How can I remove already sent push notification from users device from server?

As you probably seen apps like gmail have the ability to remove sent notification from user's device whenever they want. They do mostly when you have multiple client and wants to remove one notification when user watched one of them.

How is that possible? Any idea would be great!

Answer 1

As for clearing out notifications, try setting the badge count to 0.