Dear Apple Support Team, Hope you are doing well. Regarding my previous inquiry, it was quite extensive and contained some inaccuracies. Therefore, I have re-organized and separated the questions for clarity and would like to confirm them again. We are writing to you regarding an inquiry about the upcoming transfer of our phone application to another company. Our main question is: After this transfer, will our customers' existing systems still be able to continue using the former application as is, for a certain period? Specifically, we want to confirm if the application, once transferred to Co.B, can still be used by our current customers on their existing systems without any immediate changes or issues from Apple's side. Please refer to the attached document for more details. Thank you for your time and assistance. Sincerely,

Thank you for your reply. If this problem occurs again and I am able to get a sysdiagnose, I will contact you again.

Thank you for your advice. In the end, we decided to address the issue by changing the timer setting to a value that took into account the delays we had observed so far. This issue can be closed.

Yes. Currently, one of our corporate clients has reported an issue with my application. Upon analyzing the application log file from when the incident occurred, we identified "ENOTCONN" as the cause. We have not received similar reports from other clients. The total number of logs received is limited, and at this time we have only been able to identify the cause from the app logs in one case.

What thread does the timer target? The simplest way to delay timer firing is to block the runloop the timer is targeting. Sometimes this delays occur, and sometimes they don't. Think of timers as targeting a dedicated call-controll processing thread and not blocking the run loop. Have you set NSTimer.tolerance? While the documentation says that it defaults to "0", I'd suggest setting it to "0" yourself (assuming that what you want). I also considered NSTimer.tolerance and, as per your suggestion, explicitly set it to 0. However, this had no discernible effect, likely because its default value is already 0. Given this, do you have any other suggestions for ensuring reliable timer firing?

This only occurs in specific environments. Our app is used by many customers, but this is the first time we've detected this issue, and it's only happened once.

Purpose To clarify previous inquiries, we have reorganized our questions regarding the App Transfer of our VoIP PUSH enabled application "PhoneApp" to another company's (Company B) App Store account. Our goal is to understand the potential impact on existing users and the feasibility of conducting tests of the transfer process. Current Status App Store Publication: "PhoneApp (signed with Company A's certificate)" is currently published by Company A on the App Store. Our PUSH Server: Our PUSH server uses an APNs Authentication Key (P8 Key: Company A) to send PUSH notifications to the Apple Push Notification service (APNs). Existing Users: Existing users receive VoIP PUSH notifications from "our PUSH server (using P8 Key: Company A)" on their iPhones with "PhoneApp (signed with Company A's certificate)" installed. Q1.Regarding Continued Usage by Existing Users After PhoneApp is transferred to Company B and "PhoneApp (signed with Company B's certificate)" is published on the App Store, existing users will continue to use "PhoneApp (signed with Company A's certificate)" until they update the app. In this scenario, will "PhoneApp (signed with Company A's certificate)" on existing users' devices still be able to receive VoIP PUSH notifications from "our PUSH server (using P8 Key: Company A)" as before? We are concerned that all users might need to update their apps to "PhoneApp (signed with Company B's certificate)" simultaneously with the transfer, or that all PUSH servers might need to update their P8 Keys to "P8 Key: Company B" at the same time. This would be difficult to manage. Q2. Regarding Smooth Transition for Existing Users There will be a coexistence period where existing user environments will have both "PhoneApp (signed with Company A's certificate)" and "PhoneApp (signed with Company B's certificate)". We believe that by enabling the following functionalities in our PUSH server, we can ensure that customer operations are unaffected during this coexistence period. Is this understanding correct? Are there any other recommended best practices? When our PUSH server sends a VoIP PUSH to "PhoneApp (signed with Company A's certificate)", it makes a PUSH request to APNs using Company A's APNs Authentication Key (P8 Key: Company A). When our PUSH server sends a VoIP PUSH to "PhoneApp (signed with Company B's certificate)", it makes a PUSH request to APNs using Company B's APNs Authentication Key (P8 Key: Company B). Q3. Regarding Feasibility of Transfer Testing We believed that by temporarily maintaining the following state, we can conduct transfer tests in advance. is this impossible? I have received an answer to this question once, but I would like to re-question I am concerned that there may have been a misunderstanding for my question: Initiate the transfer of "PhoneApp" from Company A to Company B. Company B's Apple Account does not accept the transfer, maintaining a "Pending App Transfer" status. Build "PhoneApp (signed with Company B's certificate) with same bundle ID" and publish it on Company B's Apple Account via TestFlight. Install "PhoneApp (signed with Company B's certificate)" via TestFlight on test devices. The PUSH server sends a PUSH request to "PhoneApp (signed with Company B's certificate)" using "Company B's P8 Key". if above is possible, While maintaining this "Pending App Transfer" status, is it possible to perform the following transfer tests? Receive VoIP PUSH notifications using "Company B's P8 Key" on "PhoneApp (signed with Company B's certificate)". Receive VoIP PUSH notifications using "Company A's P8 Key" on existing "PhoneApp (signed with Company A's certificate)". Receive VoIP PUSH notifications using "Company A's P8 Key" on a newly installed "PhoneApp (signed with Company A's certificate)". (We also want to confirm if "PhoneApp (signed with Company A's certificate)" can still be newly installed from the App Store once the transfer process begins.)

The recipient can build their push servers and test it with another app they own, but not with the transferring app until the transfer is completed. Thank you for your previous guidance. I understood that a recipient can build their push servers and test them with another app they own, but not with the transferring app until the transfer is completed. Based on this, my plan is to first register a new app specifically for PUSH testing under the transferor's account (Company A), confirm that PUSH works, then transfer this test app to the transferee (Company B), and finally, verify PUSH functionality again after the transfer is complete. Now, I have a more specific question regarding the transfer of an existing app. For clarity, let's refer to the transferor's company as Company A, the transferee's company as Company B, and the app to be transferred as App C. Currently, App C (owned by Company A) is widely used by many users who have it installed on their devices. My primary concern is to understand what happens to these existing users' VoIP push functionality when App C is formally transferred from Company A to Company B (meaning, an App Transfer within the Apple Developer Program). Here's my specific question: After App C's ownership is transferred from Company A to Company B, will users who had Company A's App C installed on their devices (before the transfer was completed) still be able to receive VoIP push notifications sent from Company A using Company A's P8 key? My current understanding and proposed setup are as follows: I acknowledge that the P8 key for VoIP push is specific to each developer account (Team ID). So, Company A has its own P8 key, and Company B will have its own P8 key. Therefore, I plan to place Company A's P8 key and Company B's P8 key on the push server, and add a feature that uses Company A's P8 key when pushing to Company A's app C, and Company B's P8 key when pushing to Company B's app C. Because I believe that even after App C is transferred to Company B, users who installed the original App C (signed by Company A) will still be able to receive VoIP push messages if these messages are sent from Company A's push server using Company A's P8 key. Is this assumption correct? Or will the APNs server, upon completion of after the transfer, reject push requests from Company A (using Company A's P8 key) directed at the App C (even if users have the original Company A-signed version installed)? My main concern stems from this: If it's not possible for Company A to continue pushing to the existing installed base after the transfer, it would imply that all existing users would immediately lose push functionality from the moment the app transfer is completed. To regain functionality, they would then need to update their app to a version signed by Company B. This burden (requiring immediate updates from a large user base to maintain core functionality) would be significant and could cause considerable confusion. Could you please clarify the exact behavior of APNs in such an app transfer scenario, specifically regarding the continued validity of the original owner's P8 key for previously installed app versions? If my assumption is incorrect, I would greatly appreciate any guidance or recommended workarounds to mitigate the disruption for existing users during and after an app transfer. Thank you for your time and assistance.

Thank you for your previous response to my question which directed me to the Extra-ordinary Networking documentation. We have thoroughly reviewed this documentation and related articles, but have yet to find a direct solution to the specific problem we are facing. Our VoIP application is currently being operated in a customer environment utilizing an sXGP-SIM (local LTE-SIM). A specific requirement from our customer is to "always use the data communication network, rather than the voice call-specific VoLTE network, for establishing SIP and RTP traffic." What we know from our investigations so far: In the customer's sXGP environment, we have confirmed that the VoIP application (client) can successfully connect to the SIP server (server) and conduct VoIP calls (RTP), regardless of whether the connection routes through what might be conceived as a VoLTE network or a general data communication network. Following general best practices, we considered an approach where we do not explicitly call bind() when creating sockets, but instead rely on the OS for route selection (i.e., using connect() and then getsockname() to retrieve the local IP address). However, with this method, we believe it is not possible to control whether the OS-selected route becomes a VoLTE network or a data communication network, nor is it possible for the application to programmatically identify the type of network used. Given that both presumed network paths are viable for reaching the target server in the customer's environment, we cannot rule out the possibility of the OS selecting a VoLTE network path. We are seeking clarification on the following two points: 1. Identification of VoLTE vs. Data Communication Network Is there an existing iOS API (including Network Extension Framework, Network.framework, or other lower-level APIs) that allows an application to programmatically determine whether the current network path is a logical path assigned for VoLTE, or a logical path assigned for general data communication? 2. Forcing Traffic Routing to a Specific Network Path Similarly, is there an API or mechanism that allows a VoIP application to explicitly force its SIP and RTP traffic to route through a path identified as a "data communication network" and not a VoLTE network? Our team understands that implementing these features via public iOS APIs might be challenging. However, to provide a definitive answer to our customer, an official statement from Apple, especially confirming if "it's currently not feasible with iOS APIs," would be highly valuable as evidence for guiding our future development and customer communication. If such APIs or recommended design patterns do not exist, a clear confirmation of this would be greatly appreciated. Conversely, if it is indeed possible, could you please provide hints on the specific APIs or approaches? Thank you for your time and consideration.

Hi. Thank you for your advice. We will try it.

By "managed environments," I assumed you meant MDM, is that correct? If so, it depends on the client. (We have multiple clients and it varies by client) So, if there is any solution that is based on the premise of "using it in an MDM environment," I would like to know detail of about it.

Thank you for your advice. I understood the usefulness of NEAppPushProvider.handleTimerEvent(). but I found the following description in "Establish and Monitor the Network Connection" Your push provider must implement the handleTimerEvent callback method, which the framework calls every 60 seconds. Implement this method to check the status of the connection on the client end. Is the execution interval of NEAppPushProvider.handleTimerEvent fixed at 60 seconds? If it can be set to an arbitrary interval, would you tell me sample source or how to configure it.

Thank you for the advice. Following your advice, I executed PKPushRegistry on the first line of didFinishLaunchingWithOptions, and that resolved the issue. This was an experimental implementation, but we will proceed with the commercial implementation with the policy of performing PKPushRegistry as early as possible. By the way, why was it necessary to perform PKPushRegistry as early as possible? If it's not too much trouble, could you please tell me?

Since then, I have repeated the test, but the same problem has not recurred, and I have not been able to take a diagnostic log. I don't think we can investigate without the log, but could you let me know there was a similar reports or not before? Best Regards,

The method "[AppDelegateImpl voipRegistration]" is where your app creates and configures PKPushRegistry. Yes, that's correct. "[AppDelegateImpl voipRegistration]" is a log indicating that sequence number 3(PKPushRegistry) in BAADCA11.jpg was executed. The fact that it was not logged indicates that it was never called. Yes, that's correct. myApp executes the PKPushRegistry only once, at sequence number 3 in BAADCA11.jpg. I assume this is what you mean by "PKPushRegistry call for PID 405." After sequence number 3, myApp does not make any PKPushRegistry calls (it doesn't make multiple PKPushRegistry calls). The combination of 1 & 2 would mean that the termination of 512/513/514 was valid. No, I don't think so. I believe this is where our understanding differs. I believe that PKPushRegistry is an API that should be called only once when myApp starts, and not an API that should be called on a call-by-call basis of VoIP . Perhaps you think that PKPushRegistry is an API that should be called on a call-by-call basis? From here on, this is my speculation. Internally in iOS, PIDs 512, 513, and 514 may need to hold the callback destination for PKPush. However, this holding is the result of registration through the interface between internal iOS components. In the interface between iOS and the application, registering only once at myApp launch should definitely be sufficient. Could you please confirm this point and provide the results?