This issue has cropped up many times here on DevForums. Someone recently opened a DTS tech support incident about it, and I used that as an opportunity to post a definitive response here. If you have questions or comments about this, start a new thread and tag it with Network so that I see it. Share and Enjoy — Quinn “The Eskimo!” @ Developer Technical Support @ Apple let myEmail = "eskimo" + "1" + "@" + "apple.com" iOS Network Signal Strength The iOS SDK has no general-purpose API that returns Wi-Fi or cellular signal strength in real time. Given that this has been the case for more than 10 years, it’s safe to assume that it’s not an accidental omission but a deliberate design choice. For information about the Wi-Fi APIs that are available on iOS, see TN3111 iOS Wi-Fi API overview. Network performance Most folks who ask about this are trying to use the signal strength to estimate network performance. This is a technique that I specifically recommend against. That’s because it produces both false positives and false negatives: The network signal might be weak and yet your app has excellent connectivity. For example, an iOS device on stage at WWDC might have terrible WWAN and Wi-Fi signal but that doesn’t matter because it’s connected to the Ethernet. The network signal might be strong and yet your app has very poor connectivity. For example, if you’re on a train, Wi-Fi signal might be strong in each carriage but the overall connection to the Internet is poor because it’s provided by a single over-stretched WWAN. The only good way to determine whether connectivity is good is to run a network request and see how it performs. If you’re issuing a lot of requests, use the performance of those requests to build a running estimate of how well the network is doing. Indeed, Apple practices what we preach here: This is exactly how HTTP Live Streaming works. Remember that network performance can change from moment to moment. The user’s train might enter or leave a tunnel, the user might step into a lift, and so on. If you build code to estimate the network performance, make sure it reacts to such changes. Keeping all of the above in mind, iOS 26 beta has two new APIs related to this issue: Network framework now offers a linkQuality property. See this post for my take on how to use this effectively. The WirelessInsights framework can notify you of anticipated WWAN condition changes. But what about this code I found on the ’net? Over the years various folks have used various unsupported techniques to get around this limitation. If you find code on the ’net that, say, uses KVC to read undocumented properties, or grovels through system logs, or walks the view hierarchy of the status bar, don’t use it. Such techniques are unsupported and, assuming they haven’t broken yet, are likely to break in the future. But what about Hotspot Helper? Hotspot Helper does have an API to read Wi-Fi signal strength, namely, the signalStrength property. However, this is not a general-purpose API. Like the rest of Hotspot Helper, this is tied to the specific use case for which it was designed. This value only updates in real time for networks that your hotspot helper is managing, as indicated by the isChosenHelper property. But what about MetricKit? MetricKit is so cool. Amongst other things, it supports the MXCellularConditionMetric payload, which holds a summary of the cellular conditions while your app was running. However, this is not a real-time signal strength value. But what if I’m working for a carrier? This post is about APIs in the iOS SDK. If you’re working for a carrier, discuss your requirements with your carrier’s contact at Apple. Revision History 2025-07-02 Updated to cover new features in the iOS 16 beta. Made other minor editorial changes. 2022-12-01 First posted.

I try to update remoteHandle using CXCallUpdate for outgoing call, but this works only on iOS 15 but not on 17 or 18 (16 didn't test). This problem actual only for outgoing calls, but for incoming calls update works fine. func startOutgoingCall(with callID: UUID, userID: String) { let handle = CXHandle(type: .generic, value: userID) let action = CXStartCallAction(call: callID, handle: handle) callController.requestTransaction(with: action) { [weak self] error in // ... } } func updateOutgoingCall(with callID: UUID, groupID: String) { let update = CXCallUpdate() update.remoteHandle = CXHandle(type: .generic, value: groupID) provider.reportCall(with: callID, updated: update) } I also tried phoneNumber type but it seems initial handle that I set to CXStartCallAction not possible to change (value or even type). I use this handle value to implement recall by tap on call in Recents tab of system address book. But since my calls can transform from p2p to group call, I need to update handle value or find some another way to pass call identification info.

Dear Apple Carrier Relations / Engineering Team, I am writing to you from MKSmart, a leading smart card and digital security solution provider. We have successfully deployed our SM-DP+ (Subscription Management Data Preparation+) system, which is fully compliant with GSMA standards. Furthermore, MKSmart has officially achieved the GSMA SAS-SM (Security Accreditation Scheme for Subscription Management) certification. Currently, we are facing technical difficulties when attempting to download eSIM profiles onto iPhone devices. The download process fails, and we believe our SM-DP+ server address (FQDN) or Root Certificates may not yet be whitelisted or recognized by Apple’s ecosystem. To ensure a seamless experience for our customers on iOS devices, we would like to request your guidance on the following: Onboarding Process: What are the formal steps for MKSmart to have our SM-DP+ server recognized and trusted by Apple devices? Whitelisting: How can we submit our SM-DP+ FQDN and Root Certificates for Apple’s review and inclusion in the trusted list? Carrier Bundle: Does MKSmart need to coordinate with specific carrier partners to update the Carrier Bundle, or is there a direct integration path for our infrastructure? We have attached our GSMA SAS-SM certification and technical specifications for your reference. We are ready to provide any additional documentation or perform interoperability testing as required. We look forward to your guidance and a successful collaboration. Best regards, Nguyen Do Khanh Software Engineer MKSmart Joint Stock Company https:\mksmart.com.vn

I am developing a VoIP service. Usually, when receiving a VoIP Push, Callkit is exposed immediately after receiving the message and the app is designed to be used. However, there is an extremely intermittent phenomenon (not well reproduced) where the app does not wake up even when receiving a VoIP Push. And after a long time, the app wakes up and Callkit is activated. (A long time after receiving the call…) Has anyone experienced the above phenomenon? I wonder if there are any reported parts depending on the OS version. (I have identified that it does not occur in the 17.x version, but it is difficult to guarantee because it occurs extremely intermittently) The app is not running in the background, but... Could this be happening if there are a lot of pending operations in the background? I need help urgently

Hi there, How can I best understand the changes on the eSIM Installation wizard, i.e. on iOS 18 and later after an eSIM installation you used to get steps such as labeling the eSIM, deciding what to use for iMessage & FaceTime, what to use for mobile data, main voice line, etc. Whereas on iOS 26 you are not prompted for these steps.

I have an application that needs to make a USSD call, but on some devices the * and # don't work on the dialer, on others it does. if let phoneNumber = ussdNumberTextfield.text { let encoded = "telprompt:\(phoneNumber)".addingPercentEncoding(withAllowedCharacters: .urlQueryAllowed)! if let url = URL(string: encoded) { if application.canOpenURL(url){ DispatchQueue.main.async { self.application.open(url, options: [:]) { success in } } } } }

I’d like to propose that Apple consider introducing a controlled entitlement for the SIM Application Toolkit (STK) on iOS, allowing limited developer access through a secure, user-consented API layer. While I understand the historical restrictions around SIM access for privacy and carrier security, there are legitimate, high-impact use-cases in emerging markets where STK remains a critical part of everyday digital transactions. Currently, developers have no sanctioned way to trigger or interact with STK flows — which leaves millions of iPhone users unable to complete basic offline payment or authentication actions that their Android counterparts can. The Problem In regions such as Sub-Saharan Africa, South Asia, and Southeast Asia, entire financial ecosystems still depend on SIM-based STK interactions (commonly through USSD or encrypted STK sessions). On iOS: The “SIM Applications” menu is buried under Settings → Cellular → SIM Applications, often missing depending on carrier provisioning. Third-party developers cannot programmatically open or trigger STK actions. This results in incomplete or inconsistent payment experiences for iOS users — even when the same SIM card supports rich offline capabilities on Android devices. Proposed Solution Introduce a “SIMToolkitAccess” entitlement, gated behind the following controls: User Consent Prompt When first triggered, the system displays a native dialog: “App ‘X’ would like to initiate a SIM Toolkit action (e.g., payment or balance check). Do you allow this?” The user can approve once, always, or deny. Scoped Access Model Allow only STK command initiation (e.g., “Launch STK Menu,” “Send STK Request”) Prohibit background execution or passive SIM data reading. Require entitlement approval from Apple Developer Relations, similar to CarPlay, CallKit, or HealthKit. Secure Sandbox STK sessions run in a system-managed sandbox with zero data exposure to the calling app. The app simply receives a completion callback with a generic status code (e.g., .completed, .cancelled, .timeout). Key Use-Cases That Would Benefit Offline Mobile Payments (M-PESA, Airtel Money, T-Kash) Many users rely on STK-based menus for sending or receiving money, paying bills, and topping up accounts. → Enabling secure triggers from native apps would unify the payment UX between Android and iOS, increasing inclusivity. SIM-based Authentication / OTP Requests Telecoms and banks in these regions use STK channels for encrypted session-level identity verification. → Allowing STK initiation would enable secure, offline identity confirmation flows. Carrier Value-Added Services (Data Bundles, Utility Payments) Network operators still deliver bundles, electricity token purchases, and airtime loans via STK sessions. → Secure developer access would allow modern iOS apps to wrap these flows in more intuitive interfaces while maintaining carrier security. Offline Resilience / Disaster-Recovery Flows During power or data outages, STK is often the only operational payment method, as it runs directly on the GSM layer. → Allowing iOS apps to gracefully degrade to STK ensures users can still transact safely without internet access. Why It Matters This is not about exposing low-level carrier interfaces — it’s about giving developers the ability to deliver consistent, accessible, and inclusive financial experiences to iPhone users in markets where connectivity cannot be assumed. Apple’s leadership in privacy and safety would make it the perfect platform to define the secure standard for modernized STK integration — something Android’s open access model lacks. A gated entitlement model would preserve integrity while unlocking transformative use-cases for millions.

Hello, is there a way to get MCC/MNC carrier codes on iOS? I'm also wondering if there's a private API. I want to obtain network information while I am abroad to determine the country of residence.

Hello, I am working to integrate the new com.apple.developer.networking.carrier-constrained.app-optimized entitlement in my iOS 26 app so that my app can use a carrier-provided satellite network, and want to confirm my understanding of how to detect and optimize for satellite network conditions. (Ref: https://developer.apple.com/documentation/bundleresources/entitlements/com.apple.developer.networking.carrier-constrained.app-optimized ) My current approach: I plan to set the entitlement to true once my app is optimized for satellite networks. To detect if the device is connected to a satellite network, I intend to use the Network framework’s NWPath properties: isUltraConstrained — I understand this should be set to true when the device is connected to a satellite network. (Ref: https://developer.apple.com/documentation/network/nwpath/isultraconstrained ) linkQuality == .minimal — I believe this will also be set in satellite scenarios, though it may not be exclusive to satellite connections. (Ref: https://developer.apple.com/documentation/network/nwpath/linkquality-swift.enum/minimal ) Questions: Is it correct that isUltraConstrained will reliably indicate a satellite connection? Should I also check for linkQuality == .minimal, or is isUltraConstrained sufficient? Are there any additional APIs or best practices for detecting and optimizing for satellite connectivity that I should be aware of? Thank you for confirming whether my understanding and approach are correct, and for any additional guidance.

We are developing an app that includes functionality to install an eSIM. While the eSIM installation process works fine, we're unable to get the ICCID from the installed eSIM card. When querying the associatedIccid from the CTCellularPlanProperties, it returns nil. Can you advise how we can get the ICCID from an eSIM that was installed via our app?

[Question] Inconsistent Call Directory number matching across regions (Japan, Taiwan, U.S.) We’re developing a Call Directory extension and observed inconsistent number matching depending on carrier region and number format. Environment Device: iPhone (iOS 26.0) Call Directory Extension: Custom implementation Carrier A: Japan carrier SIM Carrier B: Taiwan carrier SIM Numbers added to Call Directory patterns: +81 120 580 2XXX +81 704 336 2XXX Observed Behavior (Japan Carrier SIM) Incoming call from +81 120 580 2XXX → Caller name not displayed (Call Directory match failed). Entering 0120 580 2XXX in the Phone app dialer → Name displayed correctly. Incoming call from +81 704 336 2XXX → Caller name displayed correctly. Entering 070 4336 2XXX in the Phone app dialer → Name displayed correctly. Observed Behavior (Taiwan Carrier SIM) Entering +81 120 580 2XXX in the dialer → Name not displayed until the call button is pressed. Entering +81 704 336 2XXX in the dialer → Name displayed immediately, before the call is placed. Steps to Reproduce For Japan carrier: Use a device running iOS 26 with a Japanese SIM card. Add the following numbers to the Call Directory extension: +81 120 580 2XXX and +81 704 336 2XXX Receive an incoming call from +81 120 580 2XXX → ❌ Caller name not displayed. Open the Phone app and enter 0120 580 2XXX → ✅ Caller name displayed. Receive an incoming call from +81 704 336 2XXX → ✅ Caller name displayed. Open the Phone app and enter 070 4336 2XXX → ✅ Caller name displayed. For Taiwan carrier: 7. Insert a Taiwan SIM card (keep the same Call Directory patterns). 8. Enter +81 120 580 2XXX → ❌ Name not shown until the call button is pressed. 9. Enter +81 704 336 2XXX → ✅ Name shown immediately. Expected Result For both numbers: Caller name from Call Directory should display consistently: a) On incoming calls. b) When entering the full number in the dialer (before pressing call). Behavior should be consistent across regions (Japan, Taiwan, United States). Actual Result Region / Carrier Number Pattern Incoming Call Dialer (Local Format) Japan +81 120 580 2XXX ❌ Not shown ✅ Shown (0120 580 2XXX) Japan +81 704 336 2XXX ✅ Shown ✅ Shown (070 4336 2XXX) Taiwan +81 120 580 2XXX N/A ❌ Not shown until call Taiwan +81 704 336 2XXX N/A ✅ Shown immediately Questions How should numbers be formatted or stored in the Call Directory patterns so that they match both incoming calls and dialer input consistently across regions? Are there region-specific number normalization rules (e.g., Japan’s 0-prefixed local dialing or Taiwan’s international format handling)? Is there an official guideline or recommendation for formatting phone numbers in Call Directory extensions (e.g., E.164 vs local format) to ensure consistent matching? Notes The inconsistent behavior appears to be related to how iOS normalizes numbers per carrier region and local dialing conventions. In Japan, incoming calls from mobile numbers starting with 070 match correctly, while 0120 (toll-free) fails unless entered in local format.

I'm trying to create a dialer app for iOS that will make verified cellular, not voip, calls by registering the calls on my server with an option for passphrase offline verification. This means that I want to build a dialer with a nice UX, so I'm trying to use the new default dialer capability. I've read https://developer.apple.com/documentation/livecommunicationkit/preparing-your-app-to-be-the-default-dialer-app which links to https://developer.apple.com/documentation/livecommunicationkit/startcellularconversationaction for starting a call, but when I try to actually use it in my app it says "Cannot find type 'TelephonyConversationManager' in scope" and similar, despite importing LiveCommunicationKit. Is there a default dialer example app & xcode project I can look at for how this should be set up? As I understood it I should be able to use these from iOS 18.2, and I'm targeting that version in my project. The page for StartCellularConversationAction says Beta 26.0 though, have I misunderstood something? does some flag need to be set in my xcode to be able to use this? I read that all test devices need to be in the EU, that should not be the problem.

Hello, I noticed the new entitlement in iOS 26 under LiveCommunicationKit: Preparing your app to be the default dialer app. My question is about eligibility: If a developer account is registered in the EU, can any app add the Default Dialer capability, or is it restricted only to apps that provide real calling/communication functionality (e.g., WhatsApp, Telegram, Skype)? If granted, does this capability allow the app to make/receive cellular calls and access call history, or is it limited only to VoIP-style scenarios through CallKit integration? What are the minimum functionalities required to support this feature (e.g., having a dial pad, call history screen, etc.)? Why must the developer account be registered in the EU to use this entitlement? Thanks in advance for the clarification!

I've been trying to understand what kind of UX is available if my app is using the default-dialer capability. I have found https://developer.apple.com/documentation/livecommunicationkit/preparing-your-app-to-be-the-default-dialer-app and I am in the EU. On android I built the UX I want and it's quite neat, so now I'm trying to work. out what I can get on iOS. Because the product is kind of worthless with just android. I have built a simple dialer ux with a numberpad, contact lookup etc. Then when the user presses the Call button does it have to pop up the system prompt "Call number"? Does it have to swap over to the system ui for the actual call? So there's no way to show information about the call, during the call? Or am I using the frameworks incorrectly? I am very new to iOS development. TrueCaller and others show validation, but as I understand it they pre-fetch all the data, I can't do that.

We have received some information that with the release of iOS 18, there have been notable changes in how this API behaves, can apple team shed some light on this? on ios 17 this worked without much issues, what has changed on ios 18?

I have a question. I work for a mobile operator, and when you insert the SIM, the default APN is automatically configured. However, afterward, using the internal Device Manager platform, we send the corresponding APN of an MVNO to that MSISDN. However, the iPhone device (any model, recent iOS versions) receives the notification of the APN change, but it doesn't reflect the change in the APN settings menu. Do you know how we could make the iPhone device reflect the APN change?

Hi, We have a need to provide SIM verification. At present, accessing the phone number bound to the device is not programmatically accessible. Would Apple consider exposing this API via a user consent? Otherwise, what is the suggested approach to verify the SIM card is the correct phone number on an iOS device?

I'm currently experimenting with TelephonyMessagingKit on iOS 26 Beta 3 (in the EU). I've managed to register my example project as the default Carrier messaging app, and sending/receiving SMS inside the app also appeared to work. However, I do not see any way to receive notifications/messages while the app is not running. Is this intentional? Not being able to notify users about an incoming message would be a competitive disadvantage compared to Apple's messages app, which is why I'd expect there to be an API to do this, given the EU rules. I'd appreciate any help here. Thanks!

I am developing a VoIP application that uses NetworkExtension (Local PUSH function) And VoIP(APNs) PUSH. Since iPhone X, iPhones have supported eSIM, allowing for the simultaneous use of a physical SIM and an eSIM. Consequently, users of our VoIP app have requested the ability to lock the network used by the VoIP app to either the eSIM or the physical SIM. Our VoIP app utilizes the network through the socket API. Is there an API in the iOS SDK to lock the network used via sockets to either the eSIM or the physical SIM? In other words, we would like to be able to retrieve the IP address assigned to the eSIM or the physical SIM in advance, and know which IP address is assigned to which SIM. Are there any such APIs available (that are not "Deprecated")

Hi Forum, We’re building a security-focused SDK for iOS that includes SIM Binding and SIM Swap detection to help prevent fraud and unauthorised device access, particularly in the context of banking and fintech apps. We understand that iOS limits access to SIM-level data, and that previously available APIs (such as those in CoreTelephony, now deprecated from iOS 16 onwards) provide only limited support for these use cases. We have a few questions and would appreciate any guidance from the community or Apple engineers: Q1. Are there any best practices or Apple-recommended approaches for binding a SIM to a device or user account? Q2. Is there a reliable way to detect a SIM swap when the app is not running (e.g., via system callback, entitlement, or background mechanism)? Q3. Are fields like GID1, GID2, or ICCID accessible through any public APIs or entitlements (such as com.apple.coretelephony.IdentityAccess)? If so, what is the process to request access? Q4. For dual SIM and eSIM scenarios, is there a documented approach to identify which SIM is active or whether a SIM slot has changed? Q5. In a banking or regulated environment, is it possible for an app vendor (e.g., a bank) to acquire certain entitlements from Apple and securely expose that information to a security SDK like ours? What would be the compliant or recommended way to structure such a partnership? Thanks in advance for any insights!