I have a background notification with "content-available:1" that work when app have an high battery level.
When the battery level is low (like 20%) the notification does not arrive any more or in any case it is not processed by the application handler.
Is it a normal behavior? For example Whatsapp notifications don't have this problem.
That does sound like normal behaviour, yes. The system has undocumented heuristics that it uses to decide if or when to deliver silent push notifications. If the user opens your app a lot, then it might be more likely to deliver them. In a low battery state, it might be more likely to discard them or delay delivery until a later time when the device gets woken up for some other reason.
How do you know Whatsapp doesn’t have this “problem”? If they have silent pushes being discarded, you wouldn’t see anything in the app. If you see a badge or banner, then it’s not a silent push.
