We did a test on our ionic app. We are using FCM plugin of Ionic for Push Notification and everything seems to be working as expected.
However, after going through a few GitHub issues of Push Plugin. I found out an open issue on their GitHub. I am sharing a link to the issue below. Kindly follow this issue for updates.
Also, content_available has nothing to do with foreground push notifications.
FCM Documentation on content-available parameter:
content_available: On iOS, use this field to represent
content-available in the APNs payload. When a notification or message is sent and this is set to
true, an inactive client app is awoken, and the message is sent through APNs as a silent notification and not through the FCM connection server. Note that silent notifications in APNs are not guaranteed to be delivered, and can depend on factors such as the user turning on Low Power Mode, force quitting the app, etc.
iOS Documentation on content-available parameter:
To support a background update notification, make sure that the payload’s
aps dictionary includes the
content-available key with a value of
phonegap-push-plugin on content-available parameter:
First the JSON you send from APNS will need to include
"content-available": 1 to the
aps object. The
"content-available": 1 property in your push message is a signal to iOS to wake up your app and give it up to 30 seconds of background processing
You can read about this parameter on the FCM documentation, iOS documentation and also on phonegap-push-plugin documentation.
FCM Documentation: https://firebase.google.com/docs/cloud-messaging/http-server-ref#downstream-http-messages-json
iOS Documentation: https://developer.apple.com/library/archive/documentation/NetworkingInternet/Conceptual/RemoteNotificationsPG/CreatingtheNotificationPayload.html
I hope this helps!