General: Forums subtopic: App & System Services > Networking TN3151 Choosing the right networking API Networking Overview document — Despite the fact that this is in the archive, this is still really useful. TLS for App Developers forums post Choosing a Network Debugging Tool documentation WWDC 2019 Session 712 Advances in Networking, Part 1 — This explains the concept of constrained networking, which is Apple’s preferred solution to questions like How do I check whether I’m on Wi-Fi? TN3135 Low-level networking on watchOS TN3179 Understanding local network privacy Adapt to changing network conditions tech talk Understanding Also-Ran Connections forums post Extra-ordinary Networking forums post Foundation networking: Forums tags: Foundation, CFNetwork URL Loading System documentation — NSURLSession, or URLSession in Swift, is the recommended API for HTTP[S] on Apple platforms. Moving to Fewer, Larger Transfers forums post Testing Background Session Code forums post Network framework: Forums tag: Network Network framework documentation — Network framework is the recommended API for TCP, UDP, and QUIC on Apple platforms. Building a custom peer-to-peer protocol sample code (aka TicTacToe) Implementing netcat with Network Framework sample code (aka nwcat) Configuring a Wi-Fi accessory to join a network sample code Moving from Multipeer Connectivity to Network Framework forums post NWEndpoint History and Advice forums post Network Extension (including Wi-Fi on iOS): See Network Extension Resources Wi-Fi Fundamentals TN3111 iOS Wi-Fi API overview Wi-Fi Aware framework documentation Wi-Fi on macOS: Forums tag: Core WLAN Core WLAN framework documentation Wi-Fi Fundamentals Secure networking: Forums tags: Security Apple Platform Security support document Preventing Insecure Network Connections documentation — This is all about App Transport Security (ATS). WWDC 2017 Session 701 Your Apps and Evolving Network Security Standards [1] — This is generally interesting, but the section starting at 17:40 is, AFAIK, the best information from Apple about how certificate revocation works on modern systems. Available trusted root certificates for Apple operating systems support article Requirements for trusted certificates in iOS 13 and macOS 10.15 support article About upcoming limits on trusted certificates support article Apple’s Certificate Transparency policy support article What’s new for enterprise in iOS 18 support article — This discusses new key usage requirements. Technote 2232 HTTPS Server Trust Evaluation Technote 2326 Creating Certificates for TLS Testing QA1948 HTTPS and Test Servers Miscellaneous: More network-related forums tags: 5G, QUIC, Bonjour On FTP forums post Using the Multicast Networking Additional Capability forums post Investigating Network Latency Problems forums post WirelessInsights framework documentation iOS Network Signal Strength forums post Share and Enjoy — Quinn “The Eskimo!” @ Developer Technical Support @ Apple let myEmail = "eskimo" + "1" + "@" + "apple.com" [1] This video is no longer available from Apple, but the URL should help you locate other sources of this info.

In a class, I call the following (edited to simplify, but it matches the real case). If I do this: func getData() -> someClass? { _ = someURL.startAccessingSecurityScopedResource() if let data = NSData(contentsOf: someURL as URL) { do { let unarchiver = try NSKeyedUnarchiver(forReadingFrom: data as Data) print((unarchiver.decodeObject(of: [NSArray.self, someClass.self /* and few others*/], forKey: oneKey) as? someClass)?.aProperty) if let result = unarchiver.decodeObject(of: [NSArray.self, someClass.self /* same other types*/], forKey: oneKey) as? someClass { unarchiver.finishDecoding() print("unarchived success") return result } else { unarchiver.finishDecoding() print("unarchiving failed") return someClass() } } catch { return nil } } I get a failure on log : unarchiving failed But if I comment out the print(unarchiver.decodeObject) - line 8, it works and I get unarchived success // print((unarchiver.decodeObject(of: [NSArray.self, someClass.self /* and few others*/], forKey: oneKey) as? someClass)?.aProperty) However, when I do exactly the same for another class (I've compared line by line to be sure), it works even with the print statement. What could be happening here ?

I'm a font developer. In the development process, I will revise a font and overwrite the OTF file that is currently enabled (registered) with macOS. If I then launch an app, it will immediately use the revised version of the font; while apps that are already loaded will continue to use the old version. This suggests that each app is loading new and separate font data, rather than getting it from some existing cache in memory. Yet macOS does have a "font cache" of some sort. Some apps, like TextEdit, seem to only load the fonts that they need to use. However, other apps, like Pages, load every enabled (registered) font on the OS!! (According to the Open Files list in Activity Monitor.) Given that /System/Library/Fonts/ is 625 Mb, and we can't disable any of it, isn't that a lot of data to be repeating? How many fonts is too many fonts? I can't find much documentation about the process.

I decode an object with NSKeyedArchiver (SecureCoding): typealias BoolArray = Array<Array<Bool>> let val = decoder.decodeObject(of: NSArray.self, forKey: someKey) as? BoolArray I get the following log: *** -[NSKeyedUnarchiver validateAllowedClass:forKey:] allowed unarchiving safe plist type ''NSNumber' (0x204cdbeb8) [/System/Library/Frameworks/Foundation.framework]' for key 'NS.objects', even though it was not explicitly included in the client allowed classes set: '{( "'NSArray' (0x204cd5598) [/System/Library/Frameworks/CoreFoundation.framework]" )}'. This will be disallowed in the future. I changed by adding NSNumber.self in the list : let val = decoder.decodeObject(of: [NSArray.self, NSNumber.self], forKey: someKey) as? BoolArray No more warning in log. Is there a reason for this ?

The documentation says: The caching behavior of the NSURL and CFURL APIs differ. For NSURL, all cached values (not temporary values) are automatically removed after each pass through the run loop. You only need to call the removeCachedResourceValueForKey: method when you want to clear the cache within a single execution of the run loop. The CFURL functions, on the other hand, do not automatically clear cached resource values. The client has complete control over the cache lifetimes, and you must use CFURLClearResourcePropertyCacheForKey or CFURLClearResourcePropertyCache to clear cached resource values. https://developer.apple.com/documentation/foundation/nsurl/removeallcachedresourcevalues()?language=objc Is this really true? In my experience I've had to explicitly remove cached resource values via -removeAllCachedResourceValues or removeCachedResourceValueForKey: otherwise the URL contains stale values. For example on a URL that no longer exists I attempted to read NSURLIsHiddenKey and the last value was already cached. Instead of getting a NSFileNoSuchFileError I get the old cache value unless explicitly call -removeCachedResourceValueForKey: first and I'm fairly certain the value was cached on a previous run loop churn.

I get several warnings in log: *** -[NSKeyedUnarchiver validateAllowedClass:forKey:] allowed unarchiving safe plist type ''NSNumber' (0x204cdbeb8) [/System/Library/Frameworks/Foundation.framework]' for key 'NS.objects', even though it was not explicitly included in the client allowed classes set: '{( "'NSArray' (0x204cd5598) [/System/Library/Frameworks/CoreFoundation.framework]" )}'. This will be disallowed in the future. I am not sure how to understand it: I have removed every NSNumber.self in the allowed lists for decode. To no avail, still get the avalanche of warnings. What is the key NS.objects about ? What may allowed classes set: '{( "'NSArray' be referring to ? An inclusion of NSArray.self in a list for decode ? The type of a property in a class ?

Hi, I am a UI designer and a total newbie with coding, so I have been using AI in Xcode to do all my coding for my personal project. Everything was working fine until this morning, when I tried to run my app in the simulator (I didn't even change any code from the last time I ran the simulator) and now the simulator is crashing and freezing and I have been trying to fix it with the AI recommendations, but it seems way too complicated for me to handle even with AI's help. I feel like I need to talk to an expert and guide me out of this hole. Please help. Thank you!

I have defined a class : class Item: NSObject, NSSecureCoding { var name : String = "" var color : ColorTag = .black // defined as enum ColorTag: Int var value : Int = 0 static var supportsSecureCoding: Bool { return true } Its decoder includes the following print statement to start: required init(coder decoder: NSCoder) { print(#function, "item should not be nil", decoder.decodeObject(of: Item.self, forKey: someKey))   Another class uses it: class AllItems: NSObject, NSSecureCoding { var allItems : [Item]? static var supportsSecureCoding: Bool { return true } and decodes as follows required init(coder decoder: NSCoder) { super.init() // Not sure it is necessary allItems = decoder.decodeObject(of: NSArray.self, forKey: mykey) as? [Item] print(#function, allItems) // <<-- get nil } I note: decoder returns nil at line 5 I have tried to change to decoder.decodeObject(of: [NSArray.self, NSString.self, NSColor.self, NSNumber.self], forKey: mykey)) Still get nil And, decoder of class Item is not called (no print in the log) What am I missing ?

I have noticed race conditions on macOS when tearing down and re-configuring an NEPacketTunnelProvider. My goal is to handle switching out one VPN profile for another identical/near identical one (I'll add some context for this below). The flow that I have tested was to wait for the NEVPNStatusDidChange notification to report a NEVPNStatus.disconnected state, and then start the process of re-configuring the VPN with a new profile. In practice however, I have noticed that I must wait a couple of seconds between NEVPNStatus.disconnected state being reported and setting up a new tunnel. Otherwise, the system routing table gets messed up but the VPN reports being in NEVPNStatus.connected state, resulting in a tunnel that appears healthy but can't be accessed. With this, I wanted to ask if you have any suggestions on any OS items I can observer, in order to deterministically know that the system has fully cleaned up my packet tunnel, and that I am safe to configure another? This would be much more optimal than a hard-coded delay. Additional context: Jamf is a common solution for deploying MDM configuration profiles. However, in my tests, it doesn't support Apple's recommended approach of using the PayloadIdentifier to mark profiles for replacement, as PayloadIdentifiers are automatically updated to match the PayloadUUID of that same profile on upload. Although given what I've observed, I'm not sure the Apple recommended approach would work here in any case. Additionally, it would be nice to transition from non-MDM to MDM cleanly, however, this also requires an indeterminate wait time between the non-MDM configuration being disconnected and subsequently removed, and the MDM one being configured. With these scenarios, we need to be able to add a second configuration, with possibly identical VPN settings, then remove the old one, allowing the system to transition to the new configuration. For the MDM case, the pattern I've noticed on the system is that when the current profile is suddenly deleted, the connection will go into disconnected state, then NEVPNConfigurationChange will fire. The new profile can be configured from NEVPNConfigurationChange, however some time is needed to avoid races. For non-MDM, I had experimented with an approach of polling for MDM configurations appearing. When they do, I'd remove my previous notification observers, and set up a new NEVPNStatusDidChange notification observer, to remove the non-MDM VPN configuration after. it enters a disconnected state. Following the removal, I would call a function to reconfigure the VPN with new configuration. When this logic is in place, the call to stopVPNTunnel() is made. Again, a hardcoded delay is required between stopping and removing the old configuration and setting up a new one. Thanks!

Environment: Xcode 26 iOS 26 Also tested on iOS 18 (working correctly) Description: I'm experiencing a behavior change with URL(fileURLWithPath:) when the filename starts with a tilde (~) character. On iOS 18, passing a filename like ~MyFile.txt to URL(fileURLWithPath:) treats the tilde as a literal character. However, on iOS 26, the same code resolves the tilde as the home directory, resulting in unexpected output. Minimal Example: let filename = "~MyFile.txt" let url = URL(fileURLWithPath: filename) print(url.lastPathComponent) Expected Result (iOS 18): ~MyFile.txt Actual Result (iOS 26): 924AF0C4-C3CD-417A-9D5F-733FBB8FCF29 The tilde is being resolved to the app's container directory, and lastPathComponent returns the container UUID instead of the filename. Questions: 1. Is this an intentional behavior change in iOS 26? 2. Is there documentation about this change? 3. What is the recommended approach for extracting filename components when the filename may contain special characters like ~? Workaround: Using NSString.lastPathComponent works correctly on both iOS versions: let filename = "~MyFile.txt" let result = (filename as NSString).lastPathComponent // Returns: "~MyFile.txt" ✅ Is this the recommended approach going forward?

Hello Apple Forums, We are developing an iOS application that connects to a custom BLE accessory and sends control commands to it. Our system architecture is as follows: A separate hardware device collects data and sends it to our backend server via Wi-Fi. The backend evaluates state changes and determines when the BLE accessory should update its display. The iOS app acts purely as a BLE command executor for this accessory. Our goal is to: Maintain a BLE connection with the accessory while the app is in the background. Receive state-change events from our backend server. Upon receiving such events, send a BLE command to the accessory to update its state. We understand that iOS does not allow arbitrary background execution. We would like to confirm whether there is any supported mechanism, entitlement, or program that allows: Long-running background execution for BLE control, or Server-originated events (other than APNs) to trigger background BLE actions. If this is not supported, we would appreciate confirmation that APNs (silent push) is the only supported way to trigger such background BLE actions, or guidance on any recommended alternative architectures. Thank you for your guidance.

I need to encode and decode Array<Array> SomeStruct is multiplexed in an Int The former API did work: if let format = decoder.decodeObject(forKey: someKey) as? Array<Array<SomeStruct>> { } But using the new API if let format = decoder.decodeObject(of: Array<Array<Int>>.self, forKey: someKey) { generates an error: Cannot convert value of type 'Array<Array<Int>>.Type' to expected argument type '[AnyClass]' (aka 'Array<any AnyObject.Type>') encoding is done as follows: var format = Array(repeating: Array(repeating: 0, count: 4), count: 4) // initialize the var coder.encode(format, forKey: someKey) What is the correct syntax ?

Is there any supported or recommended way to achieve user-configurable alarm volume while still using AlarmKit? Hi there! I’m currently building an alarm app on iOS using AlarmKit, and I’m running into a fundamental limitation around volume control. When using AlarmKit, alarm sounds are played at the system ringer volume. My goal is simple in concept: Allow users to set an alarm volume inside the app, and have the alarm sound play at that volume when triggered. However, AlarmKit does not provide any API to control or override the alarm volume. I’ve explored several approaches(AVSystemController, MPVolumeView...), but none achieved the desired result. Is there any supported or recommended way to achieve user-configurable alarm volume while still using AlarmKit? Any insights from developers who’ve shipped alarm apps, or from Apple engineers, would be greatly appreciated. Thanks in advance 🙏

I have a large code that I try to update to change deprecated APIs. In the former version, I used forWritingWith and forReadingWith let data = NSMutableData() let archiver = NSKeyedArchiver(forWritingWith: data) archiver.encode(myObject, forKey: theKey) if let data = NSMutableData(contentsOf: anURL) { let unarchiver = NSKeyedUnarchiver(forReadingWith: data as Data) let myObject = unarchiver.decodeObject(forKey: theKey) as! TheObjectType // <<-- returns the object That I changed to let data = NSMutableData() let archiver = NSKeyedArchiver(requiringSecureCoding: true) archiver.encode(myObject, forKey: theKey) if let data = NSMutableData(contentsOf: anURL) { do { let unarchiver = try NSKeyedUnarchiver(forReadingFrom: data as Data) let myObject = unarchiver.decodeObject(forKey: theKey) as? TheObjectType // <<-- This returns nil This builds correctly. But on execution, unarchiver.decodeObject now returns nil. I have searched extensively to find the cause to no avail. I may probably change the design to avoid NSKeyedArchiver, but that would be a huge refactoring. I probably miss something obvious. Could someone hint at the possible cause ?

I got this error despite documentation saying it exits: https://developer.apple.com/documentation/foundation/urlresourcevalues/tagnames I'm building for iPadOS 26.2

I am developing an iOS/iPadOS application and have encountered some behavior regarding Files App and security-scoped bookmarks that I would like to clarify. Additionally, I would like to report some behavior which might include a potential issue. Question1: Accessing deleted files via bookmark (Specification clarification) Our app saves file URLs as bookmarks, which file that user has selected on Files App or app-created so to open a file which user has modified previously in the next launch. When a user deletes a file in Files App (moves a file to Recently Deleted), the app can still resolve the bookmark and access the file for read/write operations. Is this behavior intended? In other words, is it correct that a bookmark can access a file that has been deleted in Files App but not permanently removed? Question2: Overwriting a file in Recently Deleted (Potential bug) We noticed that overwriting a file in Recently Deleted behaves differently depending on the method used. Current implementation 1.Create a temporary file in the same directory 2.Write content to the temporary file 3.Delete the original file ([NSFileManager removeItemAtURL:error:]) 4.Move the temporary file to the original file path ([NSFileManager moveItemAtURL:toURL:error:]) Result: The file disappears from Files App Recently Deleted. In contrast, using [NSFileManager replaceItemAtURL:withItemAtURL:] keeps the file visible in Recently Deleted. Is this difference designed behavior? If not, this may be a bug. Question3: Detecting files in Recently Deleted We want to detect whether a file resides in Recently Deleted, but we cannot find a reliable and officially supported method. Recently Deleted files appear under .Trash, but using the path alone is not a reliable method. We have tried the following APIs without success: [NSURL getResourceValue:forKey:NSURLIsHiddenKey error:] [NSURL checkResourceIsReachableAndReturnError:] [NSFileManager fileExistsAtPath:] [NSFileManager isReadableFileAtPath:] [NSFileManager getRelationship:ofDirectory:NSTrashDirectory inDomain:NSUserDomainMask toItemAtURL:error:] We could not obtain the Recently Deleted folder URL using standard APIs. [NSFileManager URLsForDirectory:NSTrashDirectory inDomains:NSUserDomainMask] [NSFileManager URLForDirectory:NSTrashDirectory inDomain:NSUserDomainMask appropriateForURL:url create:error:] Could you advise a safe and supported way to detect Recently Deleted files properly by the app?

I'm trying to understand the behavior I'm seeing here. In the following example, I have a custom @Observable class that adopts RandomAccessCollection and am attempting to populate a List with it. If I use an inner collection property of the instance (even computed as this shows), the top view identifies additions to the list. However, if I just use the list as a collection in its own right, it detects when a change is made, but not that the change increased the length of the list. If you add text that has capital letters you'll see them get sorted correctly, but the lower list retains its prior count. The choice of a List initializer with the model versus an inner ForEach doesn't change the outcome, btw. If I cast that type as an Array(), effectively copying its contents, it works fine which leads me to believe there is some additional Array protocol conformance that I'm missing, but that would be unfortunate since I'm not sure how I would have known that. Any ideas what's going on here? The new type can be used with for-in scenarios fine and compiles great with List/ForEach, but has this issue. I'd like the type to not require extra nonsense to be used like an array here. import SwiftUI fileprivate struct _VExpObservable6: View { @Binding var model: ExpModel @State private var text: String = "" var body: some View { NavigationStack { VStack(spacing: 20) { Spacer() .frame(height: 40) HStack { TextField("Item", text: $text) .textFieldStyle(.roundedBorder) .textContentType(.none) .textCase(.none) Button("Add Item") { guard !text.isEmpty else { return } model.addItem(text) text = "" print("updated model #2 using \(Array(model.indices)):") for s in model { print("- \(s)") } } } InnerView(model: model) OuterView(model: model) } .listStyle(.plain) .padding() } } } // - displays the model data using an inner property expressed as // a collection. fileprivate struct InnerView: View { let model: ExpModel var body: some View { VStack { Text("Model Inner Collection:") .font(.title3) List { ForEach(model.sorted, id: \.self) { item in Text("- \(item)") } } .border(.darkGray) } } } // - displays the model using the model _as the collection_ fileprivate struct OuterView: View { let model: ExpModel var body: some View { VStack { Text("Model as Collection:") .font(.title3) // - the List/ForEach collections do not appear to work // by default using the @Observable model (RandomAccessCollection) // itself, unless it is cast as an Array here. List { // ForEach(Array(model), id: \.self) { item in ForEach(model, id: \.self) { item in Text("- \(item)") } } .border(.darkGray) } } } #Preview { @Previewable @State var model = ExpModel() _VExpObservable6(model: $model) } @Observable fileprivate final class ExpModel: RandomAccessCollection { typealias Element = String var startIndex: Int { 0 } var endIndex: Int { sorted.count } init() { _listData = ["apple", "yellow", "about"] } subscript(_ position: Int) -> String { sortedData()[position] } var sorted: [String] { sortedData() } func addItem(_ item: String) { _listData.append(item) _sorted = nil } private var _listData: [String] private var _sorted: [String]? private func sortedData() -> [String] { if let ret = _sorted { return ret } let ret = _listData.sorted() _sorted = ret return ret } }

My app allows to save user-selected URLs in a list and browse them with a tap. A user reported that the app often shows that when browsing their saved entry for "On My iPad", it's apparently empty (it contains no files). I saved "On My iPad" in my own list some time ago and noticed that the same issue occurs. The URL seems to be correctly resolved from the saved bookmark data, but I noticed that url.startAccessingSecurityScopedResource() returns false. The other URL I saved some time ago is iCloud Drive, which I can access without issues. If I select "On My iPad" again in a file importer, create new bookmark data from it and resolve the URL from it, access works correctly. I create bookmark data like this: let data = try url.bookmarkData(includingResourceValuesForKeys: [.localizedNameKey, .pathKey, .volumeIsLocalKey]) and resolve URLs like this: let url = try URL(resolvingBookmarkData: data, bookmarkDataIsStale: &bookmarkDataIsStale) bookmarkDataIsStale is false for both the working and not working URLs for "On My iPad". The two bookmark data are different though, even if url.path is the same. What could be the issue?

Introduction: I’m encountering a consistent crash in production on iOS 26.2 (build 23C55). The crash occurs deep within libicucore when calling [NSDateFormatter dateFromString:]. Crash Summary: Exception Type: SIGSEGV (SEGV_ACCERR) Fault Address: 0xffffffff Thread: Crashed on Main Thread (Thread 0) Library: libicucore.A.dylib Code Snippet: The crash is triggered by the following method. It converts a string to an NSDate using a specific format and locale: // 获取日期date - (NSDate *)getDateWithTime:(NSString *)time formatter:(NSString *)formatterStr { NSDateFormatter *formatter = [[NSDateFormatter alloc] init]; [formatter setDateFormat:formatterStr]; formatter.timeZone = [NSTimeZone timeZoneWithName:@"Asia/Shanghai"]; formatter.locale = [[NSLocale alloc] initWithLocaleIdentifier:@"en_US_POSIX"]; return [formatter dateFromString:time]; } Backtrace: Here is the relevant part of the crash report: Incident Identifier: E24485B6-C53E-4115-A6CF-A7E4A952AD50 CrashReporter Key: 21FAC1CF-F56B-409A-98AA-351D3D2EB06C Hardware Model: iPhone18,2 Code Type: ARM-64 Parent Process: [1] Date/Time: 2026-01-12T01:32:25Z OS Version: iPhone OS 26.2 (23C55) Report Version: 105 SDK Version: 0.0.4 Exception Type: SIGSEGV Exception Codes: SEGV_ACCERR at 0xffffffff Crashed Thread: 0 Thread 0 Crashed: 0 libicucore.A.dylib 0x000000019b81def8 0x19b74a000 + 868088 1 libicucore.A.dylib 0x000000019b7da91c 0x19b74a000 + 592156 2 libicucore.A.dylib 0x000000019b8d8340 0x19b74a000 + 1631040 3 libicucore.A.dylib 0x000000019b8eae18 0x19b74a000 + 1707544 4 libicucore.A.dylib 0x000000019b8eb600 0x19b74a000 + 1709568 5 libicucore.A.dylib 0x000000019b878be4 0x19b74a000 + 1240036 6 libicucore.A.dylib 0x000000019b87ae84 0x19b74a000 + 1248900 7 libicucore.A.dylib 0x000000019b87b2dc 0x19b74a000 + 1250012 8 libicucore.A.dylib 0x000000019b9564ac 0x19b74a000 + 2147500 9 libicucore.A.dylib 0x000000019b954afc 0x19b74a000 + 2140924 10 libicucore.A.dylib 0x000000019b952794 0x19b74a000 + 2131860 11 libicucore.A.dylib 0x000000019b98689c 0x19b74a000 + 2345116 12 CoreFoundation 0x00000001895dbfe0 0x18953d000 + 651232 13 CoreFoundation 0x00000001895dbaa0 0x18953d000 + 649888 14 Foundation 0x0000000186d2029c 0x186b88000 + 1671836 15 Foundation 0x00000001874a62dc 0x186b88000 + 9560796 16 Foundation 0x00000001874a6384 0x186b88000 + 9560964 17 xxxx 0x0000000105ea6e30 -[xxxxx getDateWithTime:formatter:] + 168 and Thread 0 crashed with ARM-64 Thread State: pc: 0x000000019b81def8 fp: 0x000000016f96bc10 sp: 0x000000016f96bbd0 x0: 0x00000000ffffffff x1: 0x000000019ba1e8e0 x2: 0x0000000000000002 x3: 0x000000000000000b x4: 0x0000000000000074 x5: 0x0000000000000069 x6: 0x0000000000000000 x7: 0xfffff0003ffff800 x8: 0x000000009ba18014 x9: 0x00000001148dffd0 x10: 0x0000000000000002 x11: 0x0000000000000004 x12: 0x0000000000000220 x13: 0x0000000000000030 x14: 0x000000015b6f36b8 x15: 0x000000015cfe0000 x16: 0x00000002a19d0ff0 x17: 0x00000001f5590a70 x18: 0x0000000000000000 x19: 0x000000016f96bc30 x20: 0x0000000000000000 x21: 0x000000015cfe3200 x22: 0x000000019ba18014 x23: 0x0000000000000000 x24: 0x000000015cfe32a0 x25: 0x0000000000000003 x26: 0x0000000000000000 x27: 0x0000000000000000 x28: 0x000000015cfe3200 lr: 0x000000019b7da958 cpsr: 0x00000000a0000000

There are many units which are inverse of standard units, e.g. wave period vs Hz, pace vs speed, Siemens vs Ohms, ... Dimension can be subclassed to create the custom units. How to extend Measurement.converted( to: )? I was looking at somehow using UnitConverter and subclass to something like UnitConverterInverse. Thoughts?

On iOS 18 and lower version, my application supports automatically switching to [System settings - Personal Hotspot] directly. But on iOS 26, my application will be redirected to [System settings- Apps]. Does iOS 26 disable the behavior of directly jumping to the system hotspot page? If support, could you share the API for iOS 26?