Question: How should I migrate from Google Cloud Messaging (GCM) to Firebase Cloud Messaging (FCM) with the Notification SDK?

Question: Are previous versions of the Notification SDK Server compatible with the Android Firebase Cloud Messaging (FCM) version?

Answer: No, the Notification SDK Server from versions 4.18.x or earlier is not compatible with FCM. From version 4.19.x and later, the Notification SDK Server is able to handle FCM and GCM identifiers.

Question: On iOS, why is the notification permission not requested again when the application is re-installed?

Answer: For the notification permission to be again requested, the application must remain uninstalled for at least one day. For more information, refer to iOS Technical Note TN2265.

Question: On iOS, why does the client device not receive all the notifications that I send?

Answer: Depending on the device availability, if multiple notifications are sent, the Apple Push Notification service (APNs) may send only the last one. For more information, refer to iOS Technical Note TN2265.

Question: Why does the notification not arrive on the client device when it was successfully sent by the server?

Answer: You need to wait a few seconds after you sent the notification so that one of the success/failure callbacks is called.

Question: On iOS, why do I get an Invalid token error when a notification is sent?

Answer: This happens, for example, when the client device is connected to the development version of the Apple Push Notification service (APNs), while the server is connected to the APNs production version, or vice versa. Check useSandboxGateway in the NotificationSDKServerCredentials class and verify it is consistent with the used PKCS #12 certificate.

Question: On iOS, why is the icon badge not correctly incremented/decremented?

Answer: The icon badge can be set in the notification and is hence managed by the server. Value 0clears the icon badge, a negative value does not affect the icon badge, and any positive value is displayed in the icon badge. Once the notification is received, it is up to the client application to handle the icon badge value as needed. Usually the badge value is decremented.

Question: On iOS, why are my notifications displayed under the old application name in the notification center?

Answer: If the client device is rebooted, the device data are updated, and the correct application name is displayed in the notification center.

Question: Why do I not receive notifications on my device when sending from the server seems to be working properly?

Answer: Check the network settings on the device, your network security settings and the firewall settings. The device must be connected to the public internet.