The UIApplication background task mechanism allows you to prevent your app from being suspended for short periods of time. While the API involved is quite small, there’s still a bunch of things to watch out for. The name background task is somewhat misappropriate. Specifically, beginBackgroundTask(expirationHandler:) doesn’t actually start any sort of background task, but rather it tells the system that you have started some ongoing work that you want to continue even if your app is in the background. You still have to write the code to create and manage that work. So it’s best to think of the background task API as raising a “don’t suspend me” assertion. You must end every background task that you begin. Failure to do so will result in your app being killed by the watchdog. For this reason I recommend that you attach a name to each background task you start (by calling beginBackgroundTask(withName:expirationHandler:) rather than beginBackgroundTask(expirationHandler:)). A good name is critical for tracking down problems when things go wrong. IMPORTANT Failing to end a background task is the number one cause of background task problems on iOS. This usually involves some easy-to-overlook error in bookkeeping that results in the app begining a background task and not ending it. For example, you might have a property that stores your current background task identifier (of type UIBackgroundTaskIdentifier). If you accidentally creates a second background task and store it in that property without calling endBackgroundTask on the identifier that’s currently stored there, the app will ‘leak’ a background task, something that will get it killed by the watchdog. One way to avoid this is to wrap the background task in an object; see the QRunInBackgroundAssertion post on this thread for an example. Background tasks can end in one of two ways: When your app has finished doing whatever it set out to do. When the system calls the task’s expiry handler. Your code is responsible for calling endBackgroundTask(_:) in both cases. All background tasks must have an expiry handler that the system can use to ‘call in’ the task. The background task API allows the system to do that at any time. Your expiry handler is your opportunity to clean things up. It should not return until everything is actually cleaned up. It must run quickly, that is, in less than a second or so. If it takes too long, your app will be killed by the watchdog. Your expiry handler is called on the main thread. It is legal to begin and end background tasks on any thread, but doing this from a secondary thread can be tricky because you have to coordinate that work with the expiry handler, which is always called on the main thread. The system puts strict limits on the total amount of time that you can prevent suspension using background tasks. On current systems you can expect about 30 seconds. IMPORTANT I’m quoting these numbers just to give you a rough idea of what to expect. The target values have changed in the past and may well change in the future, and the amount of time you actually get depends on the state of the system. The thing to remember here is that the exact value doesn’t matter as long as your background tasks have a functional expiry handler. You can get a rough estimate of the amount of time available to you by looking at UIApplication’s backgroundTimeRemaining property. IMPORTANT The value returned by backgroundTimeRemaining is an estimate and can change at any time. You must design your app to function correctly regardless of the value returned. It’s reasonable to use this property for debugging but we strongly recommend that you avoid using as part of your app’s logic. IMPORTANT Basing app behaviour on the value returned by backgroundTimeRemaining is the number two cause of background task problems on iOS. The system does not guarantee any background task execution time. It’s possible (albeit unlikely, as covered in the next point) that you’ll be unable to create a background task. And even if you do manage to create one, its expiry handler can be called at any time. beginBackgroundTask(expirationHandler:) can fail, returning UIBackgroundTaskInvalid, to indicate that you the system is unable to create a background task. While this was a real possibility when background tasks were first introduced, where some devices did not support multitasking, you’re unlikely to see this on modern systems. The background time ‘clock’ only starts to tick when the background task becomes effective. For example, if you start a background task while the app is in the foreground and then stay in the foreground, the background task remains dormant until your app moves to the background. This can help simplify your background task tracking logic. The amount of background execution time you get is a property of your app, not a property of the background tasks themselves. For example, starting two background task in a row won’t give you 60 seconds of background execution time. Notwithstanding the previous point, it can still make sense to create multiple background tasks, just to help with your tracking logic. For example, it’s common to create a background task for each job being done by your app, ending the task when the job is done. Do not create too many background tasks. How many is too many? It’s absolutely fine to create tens of background tasks but creating thousands is not a good idea. IMPORTANT iOS 11 introduced a hard limit on the number of background task assertions a process can have (currently about 1000, but the specific value may change in the future). If you see a crash report with the exception code 0xbada5e47, you’ve hit that limit. Note The practical limit that you’re most likely to see here is the time taken to call your expiry handlers. The watchdog has a strict limit (a few seconds) on the total amount of time taken to run background task expiry handlers. If you have thousands of handlers, you may well run into this limit. If you’re working in a context where you don’t have access to UIApplication (an app extension or on watchOS) you can achieve a similar effect using the performExpiringActivity(withReason:using:) method on ProcessInfo. If your app ‘leaks’ a background task, it may end up being killed by the watchdog. This results in a crash report with the exception code 0x8badf00d (“ate bad food”). IMPORTANT A leaked background task is not the only reason for an 0x8badf00d crash. You should look at the backtrace of the main thread to see if the main thread is stuck in your code, for example, in a synchronous networking request. If, however, the main thread is happily blocked in the run loop, a leaked background task should be your primary suspect. Prior to iOS 11 information about any outstanding background tasks would appear in the resulting crash report (look for the text BKProcessAssertion). This information is not included by iOS 11 and later, but you can find equivalent information in the system log. The system log is very noisy so it’s important that you give each of your background tasks an easy-to-find name. For more system log hints and tips, see Your Friend the System Log. iOS 13 introduced the Background Tasks framework. This supports two type of requests: The BGAppRefreshTaskRequest class subsumes UIKit’s older background app refresh functionality. The BGProcessingTaskRequest class lets you request extended background execution time, typically overnight. WWDC 2020 Session 10063 Background execution demystified is an excellent summary of iOS’s background execution model. Watch it, learn it, love it! For more background execution hints and tips, see Background Tasks Resources. Share and Enjoy — Quinn “The Eskimo!” @ Developer Technical Support @ Apple let myEmail = "eskimo" + "1" + "@" + "apple.com" Revision History 2023-06-16 Added a link to my QRunInBackgroundAssertion post. 2022-06-08 Corrected a serious error in the discussion of BGProcessingTaskRequest. Replaced the basic system log info with a reference to Your Friend the System Log. Added a link to Background Tasks Resources. Made other minor editorial changes. 2021-02-27 Fixed the formatting. Added a reference to the Background Tasks framework and the Background execution demystified WWDC presentation. Minor editorial changes. 2019-01-20 Added a note about changes in the iOS 13 beta. Added a short discussion about beginning and ending background tasks on a secondary thread. 2018-02-28 Updated the task name discussion to account for iOS 11 changes. Added a section on how to debug ‘leaked’ background tasks. 2017-10-31 Added a note about iOS 11’s background task limit. 2017-09-12 Numerous updates to clarify various points. 2017-08-17 First posted.

We have developed an application using xamarin forms , our iOS app is working fine till iOS17 , if we upgraded our OS version to iOS18 app is not working properly. Visual studio for Mac 2022 Xcode 16 Minimum OS version 15.4 Xamarin.iOS version 16.4.023

Hello Apple Developer Team, Based on the mandate to update the APNs certificate by February 24, 2025 for certificate-based authentication, a question from the team has been brought up that maybe Apple or the community can help answer. Since our implementation uses token-based authentication, I’m seeking clarification on a couple of points: 1. Does the certificate update affect token-based connections at all? 2. What is the rationale behind updating certificates for certificate-based authentication, and are there any implications or benefits for developers using token-based authentication? Understanding these details will help us ensure our system remains compliant and optimally configured. Any guidance or further clarification you can provide would be greatly appreciated. Thank you!

I am wondering wether iOS allow apps to detect users' proxy.

My app monitors users heart beats and if critical reading is noticed, it auto -dials 911 for emergency and ambulance help. I was under the impression that auto-dial may not be permitted or possible on the platform. Can anyone confirm and provide any additional guidance on if it is possible in the newer SDK/API stack or using any 3rd party service ? Thank you in advance!!

Is it possible to integrate a button in an app that displays advertisements to support charities -without offering any direct reward to the user?

When are you guys going to fix the CarPlay issues with this new update? I use this for work and it’s really an issue. Nothing is working and it takes up entirely too much space.

Hello, I have been testing my app in iOS 18 device and while creating a server with TCP, then apple make a request for local network permission automatically. If we don't allow the permission, the connection not working. We are getting the connection timeout error even after allowing again from device setting. Has something changed in the flow for iOS 18 version? Can someone help me to solve this issue?

I have an issue that causes multiple instances of the push provider to be initialized. And I'd like to ask you what could trigger the instantiation NEAppPushProvider subclass. It seems like it's being triggered excessively. If there's documentation that I have overlooked then just show it to me and I'll be on my way. Here's the details. But really all I want to know is why is my subclass for NEAppPushProvider keeps getting initialized. If you can answer me that than maybe all these details don't really matter but here they are. Here's why I believe there's multiple push provider. I see logs for my push provider initializing but I don't see it de-initializing. I also see redundant logs showing multiple instances trying to log into my server. Each time it initializes, an additional log is added for trying to log into my server. In the app, the system saves it's configuration shortly after initialization, after saving and loading the push configuration, the app doesn't touch config. Meanwhile in the extension, after 8 or so hours, the extension starts creating a new instance of the push provider. Then a few hours later it does it again. And again. Until the watch dog kills us for wasting too much CPU. Normally on a fresh install, I'll observe turning off the wifi to call stop on the push provider and later have the push provider de-initialize. The extension maintains a socket connection to the server, the server can send it messages to display push notifications. The software runs on hospital networks, which will not have access to the internet. It seems like the connection to the server is stable from the logs. I don't detect any disconnections. I'll check with the server to confirm. In the app I call removeFromPreferences to clear out any extensions before logging in/saving push configurations. And I call saveToPreferences on the NEAppPushManager. I do this to make sure I don't have more than one push configuration saved at one time. I also have many logs looking out for this. I used the sample code from apple as the basis of the my own Push Manager. I can post code if you deem it necessary. Hope to here from you soon. Thank you.

Hello. Recently, the users of our APP have reported using our products, and they can normally receive push in Hong Kong. However, when traveling to Japan or some countries and regions in Europe, push will not be received. we checked that -the cert is valid -the server get 'sent successfully' response -used pushtry to test the cert and token and it can receive push in app

I have two recordTypes in CloudKit: Author and Book. The Book records have their parent property set to an Author, enabling hierarchical record sharing (i.e., if an Author record is shared, the participant can see all books associated with that author in their shared database). When syncing with CKSyncEngine, I was expecting handleFetchedRecordZoneChanges to deliver all Author records before their associated Book records. However, unless I’m missing something, the order appears to be random. This randomness forces me to handle two codepaths in my app (opposed to just one) to replicate CloudKit references in my local persistency storage: Book arrives before its Author → I store the Book but defer setting its parent reference until the corresponding Author arrives. Author arrives before its Books → I can immediately set the parent reference when each Book arrives. Is there a way to ensure that Author records always arrive before Book records when syncing with CKSyncEngine? Or is this behavior inherently unordered and I have to implement two codepaths?

I am trying to test using Testflight and have set up a test with a user on an account I also own which is different to me developer account. The app I believe is running in production on a separate device and is working from a user point of view, however I am not able to query the data via the console. As I said I know the user id and password as tey are mine so even when I use the Act as user service it logs in but the query is empty. I'm assuming I'm not doing anything wrong its possibly an security issue that is preventing me accessing this account. My question to the group then is how do I verify the data that is being tested?

Hey, I would love to access the users Contact (ie. the Me Card) Apple recently released the Invites app and within this app you can find the users Contacts Photo. I tried to replicate this behaviour but I currently need to match based on a name or email or something else. I have no idea how to receive this data because when using the Invites app I only remember the app asking for Contacts permission and nothing else so far. let store = CNContactStore() let keysToFetch = [CNContactImageDataAvailableKey, CNContactImageDataKey, CNContactThumbnailImageDataKey] as [CNKeyDescriptor] let email = "test@test.de" let predicate = CNContact.predicateForContacts(matchingEmailAddress: email) do { let contacts = try store.unifiedContacts(matching: predicate, keysToFetch: keysToFetch) let imageDatas: [Data] = contacts.compactMap { $0.imageData } self.images = imageDatas.map { UIImage(data: $0) ?? UIImage() } } catch { print("Error fetching contacts: \(error)") } This is how I am retrieving the Image. MAYBE someone can help me out. Thank you so far ~ Flo

When I try to promote schema to production, I get following error: Cannot promote schema with empty type 'workspace', please delete the record type before attempting to migrate the schema again However, in hierarchical root record sharing, I think it should be completely legit use case where there is empty root record (in my case workspace) to which other records reference through ->parent reference. Am I missing something? Is this weird constraint imposed on CloudKit?

Hi, I have an iPhone/watch app that measures walking/running distance. It starts a workout session records data successfully into healthkit and then ends the workout session. I can see the data in the Health app from my app and it all appears to be correct. The issue I'm having is that the Health app doesn't use my app's data in its total distance for the day. For example, I can add 1 mile of fake data (I know that's not allowed per policy) for testing and it gets successfully added but not used in the total. The health app is only using distances collected by the watch and the phone for calculating the total distance for the day and is ignoring the distance provided by my app. What could I be missing?

Hi, I'm trying to setup PIR service for live caller id lookup (in python but based on swift example: https://github.com/apple/live-caller-id-lookup-example). The swift example provides utilities for database setup and encryption, but I can't find any specification about which key is used for database encryption and how the ios system knows about this key in order to be able to construct the PIR requests. So my question is how does the PIR service communicate the secret key to ios system or vice versa? (specific to the test environment, before onboarding)

I have been working on adding a badge number count to my app, but have run into a really weird edge case. If I have a badge number on my app, delete the application and then re-install it, the badge number still persists on the app icon until I first open the app. I tried looking to see if there is a lifecycle method that is triggered upon uninstalling an app as well as if there is a specific userDefaults attribute to check in order to clear the badge, but I can't find any clear solutions. Does anyone know of a fix to this issue?

on a span of 4 months we sent 2 for nfc entitlement requests and refused , no reason nothing . i mean all we want is the ability to use nfc on passes nothing else , no idea why this is so complex . with google you don’t even need a developer account and it’s for free , here we pay and we can’t even get the full functionality the passes offer , we got the hardware and the solution but we find out we need an nfc entitlement to allow passes to have nfc ? i mean our use case is very simple instead of having barcode on the passes we want them to be via nfc and we already got the nfc hardware but we find out we need nfc entitlement which we tried requesting but getting refused with no reason at all. at least tell u what is the problem what how to fix it not outright refuse without any reason at all. if anyone got any solution please provide.

Got notification to update this certificate - there was a link to Sectigo.com where I found an attachment with that name - when I clicked it I got a box where it said to install it. Clicked the box and it was saved somewhere on my computer. Now I dont know if that's it or I need to take further actions - please help :-) Have no experience with this - my collegue who did this has stopped. Hoping for a simple answer :-) P

"As we announced in October, the Certification Authority (CA) for Apple Push Notification service (APNs) is changing. APNs will update the server certificates in sandbox on January 20, 2025, and in production on x date, 2025. To continue using APNs without interruption, you’ll need to update your application’s Trust Store to include the new server certificate: SHA-2 Root : USERTrust RSA Certification Authority certificate. To ensure a smooth transition and avoid push notification delivery failures, please make sure that both old and new server certificates are included in the Trust Store before the cut-off date for each of your application servers that connect to sandbox and production. At this time, you don’t need to update the APNs SSL provider certificates issued to you by Apple." As we are using firebase for receiving notifications and azure notification hub, I read that there is nothing we as developers need to do and will be handled by the providers right?