I am going to build a push notification application.
I am successful to send push notifications to iOS devices.
However, sometimes a device token becomes invalid, and I do not know why. I want to know how to find that a given device token is invalid.
Each device has a app, developer build or a production build.
Depending on this the apns push calls are either directed towards Apples APNS production server or its developer sandbox version.
Hence if a ApnsKeystore with a developer build is used to send notifications to production servers, the device tokens are consider invalid. (vice versa)
Also check if build and its corresponding keystore is correct each time you send a notification.