Before iOS16, we can use https://developer.apple.com/documentation/coretelephony/ctcarrier But after iOS this is deprecated and has no replacement. There are some discussions on it, eg. https://developer.apple.com/forums/thread/714876 https://developer.apple.com/forums/thread/770400 Now I asked AI, then it provided this solution, to check the serviceCurrentRadioAccessTechnology, so it this ok to check the SIM card status? var hasSIMCard = false let info = CTTelephonyNetworkInfo() if let rat = info.serviceCurrentRadioAccessTechnology, rat.values.contains(where: { !$0.isEmpty }) { hasSIMCard = true. // has RAT } BTW, I can see a lot of changes in the Core Telephony framework. https://developer.apple.com/documentation/coretelephony 1.isSIMInserted https://developer.apple.com/documentation/coretelephony/ctsubscriber/issiminserted A Boolean property that indicates whether a SIM is present. iOS 18.0+ iPadOS 18.0+ This value property is true if the system finds a SIM matching the Info.plist carrier information (MCC / MNC / GID1 / GID2). Is this ok to check SIM insert status, this seems must preconfig some info in the info.plist. 2.iOS26 provide CTCellularPlanStatus https://developer.apple.com/documentation/coretelephony/ctcellularplanstatus Can I use this to check SIM status?

https://developer.apple.com/documentation/callkit/preparing-your-app-to-be-the-default-calling-app I have 2 accounts, one for App store and one for tesing (Inhouse type). I added the capability in the Xcode project, and can run it. But when I run a Inhouse build for it on my CI server, it failed. So is the Inhouse build support this "com.apple.developer.calling-app"?

My app support ringout feature, when set Ringout, all the calls in my app will go to native, by using tel://xxx. But when my app set as the default calling app by the user. Then when user make a call from Contact, it will jump to my app, but app will will route this call to native. So there is a issue for this, then the quesion is: How to check if my app is set as default calling app?

I found this api may fail after iOS18.0 open func request(_ transaction: CXTransaction, completion: @escaping ((any Error)?) -> Void) But I can not reproduce it and it will recover after relaunch the app. Is there any issue for this or guide line after iOS18?