Dear Experts, If a user with an older device tries to download an app, and the current version of the app requires an iOS version which their device does not support, the App Store will offer them an older most-recent-compatible version instead. I've just had an enquiry from a user of my app for whom this has not worked. Specifically he has an iPad 2. He foolishly deleted my app from the device, and now the App Store will not let him re-install it. Does anyone know why this may be? Is it simply that this App Store feature does not work for devices as old as the iPad 2? Thanks.

Does anyone know if it’s possible for a WKWebView showing a web page in the app bundle - a help screen in my case - to show SF Symbols, by name? I’d like the help page to include some of the symbols that I use for buttons elsewhere in the app. Can I do this without having to make PNGs of the symbols? Thanks.

Dear Experts, Where do memory-mapped files appear in the Allocations instrument, if at all? In the screenshot below, the green "all anonymous VM" graph is almost completely explained by the purple "IO Accelerator" graph (GPU buffers, textures etc) - but there are periods at the start of each cycle (such as at the cursor position) where there is some other contribution. I have not been able to find this in the other more-specific graphs. Any ideas anyone? I have been trying to make this app better behaved memory-wise and have made a lot of progress, in particular by removing periods when two large memory allocations co-exist, and by breaking work up into chunks. It now bothers me that there is 150 MB of "anonymous VM" that I cannot explain!

Dear All, My iOS app used to work OK on macOS, but since a macOS update in-app purchases have stopped working. It seems that the storekitagent process is no longer able to save the receipt to the filesystem. Here is what I see in the system log after I do a "refresh receipt": default 22:03:47.822657+0100 storekitagent [58C16E76_SK1] Writing receipt (83905 bytes) to file:///Users/phil/Library/Containers/0407ACA7-9EE2-4E32-AA3E-101A1B38EE70/Data/StoreKit/sandboxReceipt error 22:03:47.823539+0100 kernel Sandbox: storekitagent(1382) deny(1) file-write-unlink /Users/phil/Library/Containers/0407ACA7-9EE2-4E32-AA3E-101A1B38EE70/Data/StoreKit/sandboxReceipt error 22:03:47.824306+0100 storekitagent [58C16E76_SK1] Error writing receipt (83905 bytes) to file:///Users/phil/Library/Containers/0407ACA7-9EE2-4E32-AA3E-101A1B38EE70/Data/StoreKit/sandboxReceipt: Error Domain=NSCocoaErrorDomain Code=513 "You don’t have permission to save the file “sandboxReceipt” in the folder “StoreKit”." UserInfo={NSFilePath=/Users/phil/Library/Containers/0407ACA7-9EE2-4E32-AA3E-101A1B38EE70/Data/StoreKit/sandboxReceipt, NSUnderlyingError=0x145c19f80 {Error Domain=NSPOSIXErrorDomain Code=1 "Operation not permitted"}} Note that is a sandboxReceipt on my development system, but I have a report from a user who seems to be suffering the same problem with the app store version of the app. Is anyone else seeing this? Is there a "quick hack" I can do to grant the storekitagent process permission to write to that folder?

Dear Experts, Is there a way to create a new target in Xcode that is a copy of an existing target? Specifically, I have a standard iOS app target in the project. I'd like to build a second iOS app by adding a second target to the same project. I'd like it to start as a copy of the first target, and then I'll add and remove source files and frameworks, change assets and settings etc. It seems to me that I have to create a new target and then add all the source files etc to it, and then replicate all the settings. I've tried to do this, but it isn't working - bizarrely I just see a black screen, though log messages suggest that the app is running. I am unsure about whether the two targets are sharing e.g. the Info.plist file, etc. Any advice? Thanks.

I see this warning when my app runs: Thread running at QOS_CLASS_USER_INTERACTIVE waiting on a lower QoS thread running at QOS_CLASS_DEFAULT. Investigate ways to avoid priority inversions This is true; I know what is going on. I'd like this other thread to have a higher priority. But how do I set the "QOS class" for a thread? Searching developer.apple.com for QOS_CLASS_USER_INTERACTIVE doesn't find much. It seems that dispatch queues have priorities, but in this case I have a thread, not a dispatch queue. Any ideas?

Dear Experts, NSLocale has a notification NSCurrentLocaleDidChangeNotification and a property autoupdatingCurrentLocale ("A locale which tracks the user’s current preferences"). These suggest that an app should be able to detect when the user changes their language preference while running, or when it is resumed from the background. In practice, when I change language in the Settings app (either globally or just for my app), the app is terminated by iOS and restarts with new locale. Is this the expected behaviour? I am wondering if there is something I need to do to advertise that the app can adopt language changes without restarting, or something. Maybe only date-time formats, etc., trigger the notification but language changes don't?

I've just downloaded Xcode 15 (3.18 GB), and when I start it it downloads "additional components". It's currently downloading "iOS 17.0 Simulator" (7.56 GB). I don't need the simulator, but I do need to compile for iOS and run on devices. Do I need this "simulator" download? I note that while the small download progress window says "iOS 17.0 Simulator (21A328)", the main Xcode window won't let me compile/run the project because it is "Downloading iOS 17.0..." - though I'm not sure if the "..." at the end of that is a truncation eliding the word "Simulator".

I'm referring to the use of a "settings bundle" plist to cause the main Settings app to display your app's preferences which the app can then read via NSUserDefaults, as described here: https://developer.apple.com/library/archive/documentation/Cocoa/Conceptual/UserDefaults/Preferences/Preferences.html#//apple_ref/doc/uid/10000059i-CH6 I am wondering if this is actually deprecated, or something. I ask because, (1), it still has the high-quality old-style documentation, and (2) there doesn't seem to be a "required reason API" code for using it. Specifically, the NSUserDefaults required reason API codes are CA92.1 : "This reason does not permit reading information that was written by other apps or the system" 1C8F.1 : "This reason does not permit reading information that was written by apps, app extensions, or App Clips outside the same App Group or by the system." C56D.1: "...third-party SDK..." - nope. AC6B.1: "... com.apple.configuration.managed ..." - nope. None of the codes permit reading preferences that have been set by the Settings app using this method.

Dear Experts, In "limited access" photos mode, I present a PHPickerViewController. It shows the entire photo library, with a note at the top saying that the app can only access the items that I select. I select a photo. In the delegate method, I get a PHPickerResult containing a plausible-looking string for the assetIdentifier. It's the same string that I get for that photo in "full access" mode. Should this photo now be accessible, or do I need to do something else at this point? When I call fetchAssetsWithLocalIdentifiers using this assetIdentifier, I get no results. When I call cloudIdentifierMappingsForLocalIdentifiers, I get error PHPhotosErrorIdentifierNotFound. In "full access" mode, both work OK. What am I missing? Thanks.

I'm using CMMotionManager startDeviceMotionUpdatesUsingReferenceFrame: CMAttitudeReferenceFrameXTrueNorthZVertical and have set the NSMotionUsageDescription ("Privacy - Motion Usage Description") property in the info.plist. But I don't see a permissions popup. I also don't see any mention of this in the app's section of the Settings app. When is this usage description string used? I wonder if there is some connection between the motion permission and the location permission, which I also use?

Does anyone know how battery state notification (UIDevice.batteryStateDidChangeNotification) is supposed to work regarding app foreground/background state? Assume there is no other reason why the app is running in the background. I have enabled UIDevice.current.isBatteryMonitoringEnabled when the app was in the foreground. What should happen if the external power is later connected or removed when the app is in the background? The docs don't mention this. Possibilities include I don't get a notification, so I should check the state myself when the app next comes to the foreground. I'll get a notification when the app next comes to the foreground, if the state changed while it was in the background. The app will be woken up in the background to receive the notification. The app will be kept running in the background while isBatteryMonitoringEnabled is true. It looks as if it's doing either 3 or 4, which I find a bit surprising. But is this influenced by the fact that it's connected (wirelessly) to the debugger?

Dear Experts, I have been looking at thr SimpleWatchConnectivity sample code: https://developer.apple.com/documentation/watchconnectivity/transferring-data-with-watch-connectivity There are a couple of things in there that look out of date. Firstly, it uses a WKApplicationDelegate to receive the background tasks. I believe this can probably be entirely removed, and replaced with .backgroundTask(.watchConnectivity) { ... } on the App. Is that true? What do I need something inside the { ... } there? Secondly, it is using NSNotificationCenter to send received data from the WCSessionDelegate to the SwiftUI view hierarchy. Is there a better way to do that? I have spent a while trying to work out how a WCSessionDelegate class can connect to a binding to a SwiftUI @State property, and cause the UI to update in response to received data, but I haven't made it work. Are there any newer examples of how to do this? I'm currently only trying to send some simple applicationContext state from the phone to the watch and have some views update to show the latest values. Thanks, Phil.

Consider this Swift struct: public struct Example { public func foo(callback: ()->Void) { .... } public func blah(i: Int) { .... } .... } Using Swift/C++ interop, I can create Example objects and call methods like blah. But I can't call foo because Swift/C++ interop doesn't currently support passing closures (right?). On the other hand, Swift/objC does support passing objC blocks to Swift functions. But I can't use that here because Example is a Swift struct, not a class. So I could change it to a class, and update everything to work with reference rather than value semantics; but then I also have to change the objC++ code to create the object and call its methods using objC syntax. I'd like to avoid that. Is there some hack that I can use to make this possible? I'm hoping that I can wrap a C++ std::function in some sort of opaque wrapper and pass that to swift, or something. Thanks for any suggestions!

I would like to be able to write something like: struct FooView: View { let foo: Foo; var body: some View { assert(foo.valid); ...... } }; but of course I can't, because "Type () cannot conform to View". What's the best way to achieve this?