Server side push messaging uses cloud infrastructure on both Android and iOS devices. Some applications choose to make these notifications more 'secure' by not

Server side push messaging uses cloud infrastructure on both Android and iOS devices. Some applications choose to make these notifications more 'secure' by not sending any content through them, just the fact that you have a new notification, but that makes the UX a little less friendly. https://en.wikipedia.org/wiki/Apple_Push_Notification_service https://en.wikipedia.org/wiki/Apple_Push_Notification_servic... https://en.wikipedia.org/wiki/Firebase_Cloud_Messaging https://en.wikipedia.org/wiki/Firebase_Cloud_Messaging