How to trigger the app icon notification badge when there is a new content card

Hi everyone!! We have implemented contents cards in our apps (iOS -Android) and we want to use them to re-activate inactive users and improve engagement. So that if a user receives a new card in his Inbox, we want to activate the red badge that appears on the app icon so the user will want to enter the app to see the new notification.

The problem is that in Android we have not found a solution to activate the badge other than sending a push message, which is not the desired solution, because in this case what generates the visit is not the content card, but the push message. For iOS our team is looking to implement a silent push that can be trigger every time there is a new card, but in Android is not possible. 

Any ideas? How do you notify your users when they have a new card in the Inbox? Thanks!