Push notifications are sent to:
- Android apps (version 4.4 and above) – via FCM (Firebase Cloud Messaging),
- iOS apps (version 10 and above) – via APNS (Apple Push Notification service),
- Android apps on HUAWEI devices via HUAWEI Push Kit.
Push is part of the Notification Server, so notifications that are not delivered as Push can be forwarded via any other channel, for example, Viber or SMS. This saves messaging costs significantly.