I just took a look at Is Silent Remote Notifications possible if user has disabled push for the app?.
It basically says the Silent Notifications disregard notification settings for user. It then says:
Users still have the ability to switch off your app’s ability to process a “silent push” by means of the “Background App Refresh” control. Even though Apple Push Notification service (APNs) will deliver a push marked “content-available” to your phone, the OS will not wake up your app to receive it, effectively dropping it on the floor.
This is confusing to me. I want to make silent notifications go out only while the app is open, to update state of the app while in use only. So I wouldn't care if background app refresh is off because I wouldn't need to "wake up [my] app to receive it".
Secondarily Silent push notifications only delivered if device is charging and/or app is foreground talks about needing to have your phone plugged in to receive these notifications.
Both questions are from iOS 8, which is quite a ways back. Do they hold up all this time?