Remotely remove previously sent notification

Question

Since iOS 10 and UNUserNotificationCenter, a lot of things can be achieved with notifications, but I can't figure out how to remotely remove a push notification every time.

Using the mutable-content attribute, I'm able to modify the content of my push notification. But let's say I want to remove it later (the content has expired). I used content-available and then the following code:

UNUserNotificationCenter.current()
                        .removeDeliveredNotifications(withIdentifiers: [xxx])

It almost works, except (and that's a major problem) when the app was swiped out of memory by the user.

Has anyone found a way to remove notifications?

Outside

Answer 1

As mentioned in this SO answer we have to send another push notification to clear previously sent notifications.

That notification should contain badge:0, and omit the alert and sound fields, then it will remove notifications from notification centre as well as clear app badge.

Prosper