Background tasks don't behave as you want it to, there's no such thing as deterministic background scheduling in iOS, it simply just does not exist. The time you specify to run is not an absolute time, it is an earliest possible time, totally not the same thing. The documentation says "The delay between the time you schedule a background task and when the system launches your app to run the task can be many hours." That does not go far enough in explanation, not only can it be many hours later than you specified, the OS may not run the task at all, there are no guarentees it will get run. If the user isn't regularly engaging with your app, then the OS will stop running the tasks. This question comes up time and time and time again, people want to know how to regularly perform a task at repeating deterministic internals in the background, well you cannot, iOS just does not provide the ability to do that.

There is an API to obtain the phone number(s) in the phone and whether a number is active or not. However it's a carrier api, this means Apple allows apps to use it provided they are developed by a carrier. Presumably you are not a carrier, therefore there is no way you can determine the phone number nor when a sim is changed.

Is b1 a non-negative integer

Make sure you don't have VPN enabled - VPN can radically affect in a bad way Xcode's ability to connect with, detect a phone, or accurately detect a phone's connected state. If ever you're in a situation where something like Apple Configurator can see a device and says its connected, but Xcode disagrees with this, then its probably VPN.

What sort of problems are people having? If you have an error in what/how you are registering the numbers in the extension then that can manifest in users being able to initially turn on the extension in settings. If people have just downloaded your app for the first time then you presumably don't have content yet though? You said you attempted to reproduce in the simulator.This feature doesn't exist in the simulator. Are you therefore saying you released this without fist testing on hardware?

This is a developer forum, not an Apple user complaint forum. But maybe you have just got the Call on Other Devices feature turned on, which absolutely is turnoff able in iOS 17. I have 7 iPhones with iOS 17 with the same account, the call history is not synchonized on any of them.

And here's another problem with notification service extensions is if it has the entitlement com.apple.developer.usernotifications.filtering then it can NEVER detect the light/dark mode because com.apple.developer.usernotifications.filtering ALWAYS returns light. This isn't the first time I've seen com.apple.developer.usernotifications.filtering interfere with things, this is now the 3rd bug I've found that only manifests when a NSE has this entitlement.

You have a major misunderstanding about compilation errors, if you had a compilation error then your app would not even run. A compilation error means there is a syntactical error in your code, and it is nothing to do with a run time error. You probably have an exception, in which case add code like this at the start of your app and then add a breakpoint to the logging line. The breakpoint will be hit when you run the app if that is the problem, then you can see the call stack. func registerExceptionHandler() { NSSetUncaughtExceptionHandler { (exception) in NSLog("‼️‼️ Uncaught exception (String(describing: exception.reason))") } } You can also extract a crash stack from the phone using Xcode

"Can we trust that this update will be executed on the defined schedule". Absolutely not, read the documentation more closely. It'll probably run, but you can't specify when, nor be sure it will. You can also just update it when the user loads the app? Surely it's not going to take hours to download, or even minutes, even if there's a lot of data. You can start a background thread when the user launches the app so it wouldn't hang the ui.

You don't say what version of RN you're using. There's several issues people encountered when first using Xcode 15 https://github.com/facebook/react-native/issues/37748. https://stackoverflow.com/questions/77192195/react-native-0-71-8-build-failed-on-xcode-15

They both have the same bundle id so you can't. The only way to do so would be to temporarily change the bundle id of the TF version. Why do you need to have both installed simultaneously? You say "we" so surely you must have more than one phone? So why do both versions have to be on the same phone?

https://developer.apple.com/videos/play/wwdc2023/10006/

I don't know the answer, but I once tried posting a notification from a background asset extension which didn't work. However all the extensions seem a bit different in what they can/cannot do. Why don't you just try it and see what happens, should only take a few minutes coding.

No. But why would you want to do this? The app itself is capable of detecting the iOS version

I've not noticed them living longer than 30 seconds. How are you confirming that? If you have the Xcode debugger attached that might affect the lifetime