Testing Environment:
iOS: 26.0 Beta 7
Xcode: Beta 6
Description:
We are implementing the new BGContinuedProcessingTask API introduced in iOS 26. We have followed the official documentation and WWDC session guidance to configure our project.
The Background Modes (processing) and Background GPU Access capabilities have been added in Xcode.
The com.apple.developer.background-tasks.continued-processing.gpu entitlement is present and set to in the .entitlements file.
The provisioning profile details viewed within Xcode explicitly show that the "Background GPU Access" capability and the corresponding entitlement are included.
Despite this correct configuration, when running the app on supported hardware (iPhone 16 Pro), a call to BGTaskScheduler.supportedResources.contains(.gpu) consistently returns false.
This prevents us from setting request.requiredResources = .gpu. As a result, when the BGContinuedProcessingTask starts without the GPU resource flag, our internal Metal-based exporter attempts to access the GPU and is terminated by the system, throwing an IOGPUMetalError: Insufficient Permission (to submit GPU work from background).
We have performed extensive debugging, including a full reset of the provisioning profile (removing/re-adding capabilities, toggling automatic signing, cleaning build folders, and reinstalling the app), but the issue persists. This strongly suggests a bug in the iOS 26 beta where the runtime is failing to correctly validate a valid entitlement.
Additionally, we've observed inconsistent behavior across devices. On an A16-based iPad, the task submits successfully (BGTaskScheduler.submit does not throw an error), but the launch handler is never invoked by the system. On the iPhone 16 Pro, the handler is invoked, but we encounter the supportedResources issue described above. This leads us to ask for clarification on the exact hardware requirements for this feature. We hypothesize that it may be limited to devices that support Apple Intelligence (A17 Pro and newer). Could you please confirm this and provide official documentation on the device support criteria?
Steps to Reproduce:
Create a new Xcode project.
In Signing & Capabilities, add "Background Modes" (with "Background processing" checked) and "Background GPU Access".
Add a permitted identifier (e.g., "com.company.test.*") to BGTaskSchedulerPermittedIdentifiers in Info.plist.
In application(_:didFinishLaunchingWithOptions:) or a ViewController's viewDidLoad, log the result of BGTaskScheduler.shared.supportedResources.contains(.gpu).
Build and run on a physical, supported device (e.g., iPhone 16 Pro).
Expected Results:
The log should indicate that BGTaskScheduler.shared.supportedResources.contains(.gpu) returns true.
Actual Results:
The log shows that BGTaskScheduler.shared.supportedResources.contains(.gpu) returns false.
Processes & Concurrency
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I work for a large medical device company.
We have a 1st party BLE enabled medical device that must be very battery efficient. To this end, if a connection is lost, the BLE radio is powered down after 60 seconds and will only turn back on when a physical button on the device is pressed.
I've been tasked with connecting to the device, staying connected to the device, and being able to retrieve data from the device upon a timed action. For instance, this could include a data read and transmission while they sleep. The key part of this is staying reliably connected for extended periods of time.
This is a BYOD setup, and we cannot control power profiles.
I would very much appreciate any information, recommendations, and/or insights into solving this problem.
Thanks!
Topic:
App & System Services
SubTopic:
Processes & Concurrency
Tags:
External Accessory
iOS
Application Services
Core Bluetooth
Hi,
We are running into issues with iOS app prewarming, where the system launches our app before the user has entered their passcode.
In our case, the app stores flags, counters, and session data in UserDefaults and the Keychain. During prewarm launches:
UserDefaults only returns default values (nil, 0, false). We have no way of knowing whether this information is valid or just a placeholder caused by prewarming.
Keychain items with kSecAttrAccessibleAfterFirstUnlockThisDeviceOnly are inaccessible, which can lead to broken business logic (the app can assume no session exists).
No special launch options or environment variables appear to be set.
We can reproduce this 100% of the time by starting a Live Activity in the app before reboot.
Here’s an example of the workaround we tried, following older recommendations:
__attribute__((constructor))
static void ModuleInitializer(void) {
char* isPrewarm = getenv("ActivePrewarm");
if (isPrewarm != NULL && isPrewarm[0] == '1') {
exit(0); // prevent prewarm launch from proceeding
}
}
On iOS 16+, the ActivePrewarm environment variable doesn’t seem to exist anymore (though older docs and SDKs such as Sentry reference it).
We also tried listening for UIApplication.protectedDataDidBecomeAvailableNotification, but this is not specific to prewarming (it also fires when the device gets unlocked) and can cause watchdog termination if we delay work too long.
Questions:
Is there a supported way to opt out of app prewarming?
What is the correct way to detect when an app is being prewarmed?
Is the ActivePrewarm environment variable still supported in iOS 16+?
Ideally, the UserDefaults API itself should indicate whether it is returning valid stored values or defaults due to the app being launched in a prewarm session.
We understand opting out may impact performance, but data security and integrity are our priority. Any guidance would be greatly appreciated.
Hello,
I'm running into an issue with a complex macOS application (non-AppStore) structure involving an unsandboxed system daemon and a sandboxed SSO Extension attempting to communicate via XPC Mach service.
The macOS app is composed of three main components:
Main App: unsandboxed, standard macOS application.
System Daemon: unsandboxed executable installed with a .plist to /Library/LaunchDaemons/ and loaded by launchd. It exposes an XPC Mach Service.
SSO Extension: a sandboxed Authentication Services Extension (ASAuthorizationProviderExtension).
Main App to System Daemon communication works perfectly. The unsandboxed main app can successfully create and use an XPC connection to the System Daemon's Mach service.
But SSO Extension cannot establish an XPC connection to the System Daemon's Mach service, despite using the recommended temporary exception entitlement. I have added the following entitlement to the SSO Extension's entitlements file:
<key>com.apple.security.temporary-exception.mach-lookup.global-name</key>
<array>
<string>my.xpc.service.system.daemon</string>
</array>
(The name my.xpc.service.system.daemon is the exact name registered by the System Daemon in its Launch Daemon plist's MachServices dictionary.)
When the SSO Extension attempts to create the connection, the following log output is generated:
default 08:11:58.531567-0700 SSOExtension [0x13f19b090] activating connection: mach=true listener=false peer=false name=my.xpc.service.system.daemon
default 08:11:58.532150-0700 smd [0xb100d8140] activating connection: mach=false listener=false peer=true name=com.apple.xpc.smd.peer[1575].0xb100d8140
error 08:11:58.532613-0700 smd Item real path failed. Maybe the item has been deleted?
error 08:11:58.532711-0700 SSOExtension Unable to find service status () error: 22
The error Unable to find service status () error: 22. Error code 22 typically translates to EINVAL (Invalid argument), but in this context, it seems related to the system's ability to find and activate the service for the sandboxed process.
Questions:
Is the com.apple.security.temporary-exception.mach-lookup.global-name entitlement sufficient for a sandboxed SSO Extension to look up a system-wide Launch Daemon Mach service, or are there additional restrictions or required entitlements for extensions?
The smd log output Item real path failed. Maybe the item has been deleted? seems concerning. Since the unsandboxed main app can connect, this suggests the service is running and registered. Could this error indicate a sandbox permission issue preventing smd from verifying the path for the sandboxed process?
Are there specific sandboxing requirements for Mach service names when communicating from an Extension versus a main application?
Any guidance on how a sandboxed SSO Extension can reliably connect to an unsandboxed, non-app-group-related system daemon via XPC Mach service would be greatly appreciated!
What’s the recommended way to recursively walk through a directory tree using File Coordination? From what I understand, coordinating a read of a directory only performs a “shallow” lock; this would mean that I’d need to implement the recursive walk myself rather than use FileManager.enumerator(at:includingPropertiesForKeys:options:errorHandler:) plus a single NSFileCoordinator.coordinate(with:queue:byAccessor:) call.
I’m trying to extract information from all files of a particular type, so I think using NSFileCoordinator.ReadingOptions.immediatelyAvailableMetadataOnly on each file before acquiring a full read lock on it (if it’s the right file type) would make sense. Am I on the right track?
I am currently developing a macOS app that can show system HUDs in the Notch
Till Sequoia I used to kill the OSDUIHelper process (which displays the default macOS Volume and Brightness control HUDs) - and replaced it with my app's HUDs
But, it is not working on macOS Tahoe anymore as the OSDUIHelper process is no longer there due to the UI changes
Has the process been renamed - or is there any other way to kill the process?
Topic:
App & System Services
SubTopic:
Processes & Concurrency
Tags:
Swift
macOS
SwiftUI
Background Tasks
Hi All,
I'm working on an app that needs to connect to BLE device and on defined schedules download data from the device. the amount of data is segnificant and might take around a minute to download. we tought about utilizing both state restoration and preservation for app waking and scheduling (triggered by the ble peripheral) and BGTaskScheduler to schedule a task that will handle a long running task to manage the full data download. now, will this solution in general valid? isnt it a "hack" that goes around the 10s limit that state restoration enforces?
i know there are limitations for BGTask (like when it runs, it might be terminated by the system etc) but considering that, can we proceed with this approach without breaching apple guidelines?
thank you in advance!
Topic:
App & System Services
SubTopic:
Processes & Concurrency
Tags:
Background Tasks
Core Bluetooth
I have an app for macOS that is built using Mac Catalyst. I need to perform some background processing. I'm using BGProcessingTaskRequest to schedule the request. I have also integrated CKSyncEngine so I need that to be able to perform its normal background processing.
On iOS, when the user leaves the app, I can see a log message that the request was scheduled and a bit later I see log messages coming from the actual background task code.
On macOS I ran the app from Xcode. I then quit the app (Cmd-q). I can see the log message that the request was scheduled. But the actual task is never run. In my test, I ran my app on a MacBook Pro running macOS 26.0. When I quit the app, I checked the log file in the app sandbox and saw the message that the task was scheduled. About 20 minutes later I closed the lid on the MacBook Pro for the night. I did not power down, it just went to sleep. Roughly 10 hours later I opened the lid on the MacBook Pro, logged in, and checked the log file. It had not been updated since quitting the app. I should also mention that the laptop was not plugged in at all during this period.
My question is, does a Mac Catalyst app support background processing after the user quits the app? If so, how is it enabled?
The documentation for BGProcessingTaskRequest and BGProcessingTask show they are supported under Mac Catalyst, but I couldn't find any documentation in the Background Tasks section that mentioned anything specific to setup for Mac Catalyst.
Running the Settings app and going to General -> Login Items & Extension, I do not see my app under the App Background Activity section. Does it need to be listed there? If so, what steps are needed to get it there?
If this is all documented somewhere, I'd appreciate a link since I was not able to find anything specific to making this work under Mac Catalyst.
Topic:
App & System Services
SubTopic:
Processes & Concurrency
Tags:
CloudKit
macOS
Mac Catalyst
Background Tasks
As far as I understand, the main thread has a run loop.
When an iOS app launches, the process must keep the run loop running to stay alive.
Does that mean the main thread is the very first thread created when the process starts?
I've experimentally seen that the notifications(named:) API of NotificationCenter appears to buffer observed notifications internally. In local testing it appears to be limited to 8 messages. I've been unable to find any documentation of this fact, and the behavior seems like it could lead to software bugs if code is not expecting notifications to potentially be dropped. Is this behavior expected and documented somewhere?
Here is a sample program demonstrating the behavioral difference between the Combine and AsyncSequence-based notification observations:
@Test
nonisolated func testNotificationRace() async throws {
let testName = Notification.Name("TestNotification")
let notificationCount = 100
var observedAsyncIDs = [Int]()
var observedCombineIDs = [Int]()
let subscribe = Task { @MainActor in
print("setting up observer...")
let token = NotificationCenter.default.publisher(for: testName)
.sink { value in
let id = value.userInfo?["id"] as! Int
observedCombineIDs.append(id)
print("🚜 observed note with id: \(id)")
}
defer { extendLifetime(token) }
for await note in NotificationCenter.default.notifications(named: testName) {
let id: Int = note.userInfo?["id"] as! Int
print("🚰 observed note with id: \(id)")
observedAsyncIDs.append(id)
if id == notificationCount { break }
}
}
let post = Task { @MainActor in
for i in 1...notificationCount {
NotificationCenter.default.post(
name: testName,
object: nil,
userInfo: ["id": i]
)
}
}
_ = await (post.value, subscribe.value)
#expect(observedAsyncIDs.count == notificationCount) // 🛑 Expectation failed: (observedAsyncIDs.count → 8) == (notificationCount → 100)
#expect(observedCombineIDs == Array(1...notificationCount))
print("done")
}
Hi there,
I'm trying to work on an architecture where one app exposes an API (Extension Host) that other apps can plugin to. I've been reading all I can from the docs and whatever I can find online. It seemed like iOS26 added the ability to do such a thing (at least in early builds).
Is that the case?
Has the functionality been walked back such that extensions can only be loaded in iOS from within the single app bundle?
My use case is the following:
I'm working on an agent app that desires to have 3rd party developers add functionality (think how MCP servers add functionality to LLMs). The 3rd party plugins would be provided in their own app bundles vetted by the AppStore review team, of course, and would only provide hooks, basically, the main app can use to execute functions or get state.
This is the best thread I found on the topic, and the subtext is that it needs to be in the same bundle. https://developer.apple.com/forums/thread/803896?answerId=865314022#865314022
Let's say for the moment that this isn't possible using ExtensionKit. What's the best way to achieve this? Our current best alternative idea is a hidded WebKit window that runs JS/WASM but that's so hackish.
Please let me know, thanks!
To establish a privileged helper daemon from a command line app to handle actions requiring root privileges I still use the old way of SMJobBless. But this is deprecated since OSX 10.13 and I want to finally update it to the new way using SMAppService.
As I'm concerned with securing it against malicious exploits, do you have a recommended up-to-date implementation in Objective-C establishing a privileged helper and verifying it is only used by my signed app?
I've seen the suggestion in the documentation to use SMAppService, but couldn't find a good implementation covering security aspects. My old implementation in brief is as follows:
bool runJobBless () {
// check if already installed
NSFileManager* filemgr = [NSFileManager defaultManager];
if ([filemgr fileExistsAtPath:@"/Library/PrivilegedHelperTools/com.company.Helper"] &&
[filemgr fileExistsAtPath:@"/Library/LaunchDaemons/com.company.Helper.plist"])
{
// check helper version to match the client
// ...
return true;
}
// create authorization reference
AuthorizationRef authRef;
OSStatus status = AuthorizationCreate (NULL, kAuthorizationEmptyEnvironment, kAuthorizationFlagDefaults, &authRef);
if (status != errAuthorizationSuccess) return false;
// obtain rights to install privileged helper
AuthorizationItem authItem = { kSMRightBlessPrivilegedHelper, 0, NULL, 0 };
AuthorizationRights authRights = { 1, &authItem };
AuthorizationFlags flags = kAuthorizationFlagDefaults | kAuthorizationFlagInteractionAllowed | kAuthorizationFlagPreAuthorize | kAuthorizationFlagExtendRights;
status = AuthorizationCopyRights (authRef, &authRights, kAuthorizationEmptyEnvironment, flags, NULL);
if (status != errAuthorizationSuccess) return false;
// SMJobBless does it all: verify helper against app and vice-versa, place and load embedded launchd.plist in /Library/LaunchDaemons, place executable in /Library/PrivilegedHelperTools
CFErrorRef cfError;
if (!SMJobBless (kSMDomainSystemLaunchd, (CFStringRef)@"com.company.Helper", authRef, &cfError)) {
// check helper version to match the client
// ...
return true;
} else {
CFBridgingRelease (cfError);
return false;
}
}
void connectToHelper () {
// connect to helper via XPC
NSXPCConnection* c = [[NSXPCConnection alloc] initWithMachServiceName:@"com.company.Helper.mach" options:NSXPCConnectionPrivileged];
c.remoteObjectInterface = [NSXPCInterface interfaceWithProtocol:@protocol (SilentInstallHelperProtocol)];
[c resume];
// call function on helper and wait for completion
dispatch_semaphore_t semaphore = dispatch_semaphore_create (0);
[[c remoteObjectProxy] callFunction:^() {
dispatch_semaphore_signal (semaphore);
}];
dispatch_semaphore_wait (semaphore, dispatch_time (DISPATCH_TIME_NOW, 10 * NSEC_PER_SEC));
dispatch_release (semaphore);
[c invalidate];
[c release];
}
We added the com.apple.developer.background-tasks.continued-processing.gpu key to the entitlement file and set it to true, but BGTaskScheduler.supportedResources does not include gpu. How can we configure it to obtain permission for GPU access in the background?
Test device: iPhone 16 Pro Max, iOS 26 release version.
Started a new X-Code Project after updating to 26.0.1 and realized that I get an error when trying to mark a class as ObservableObject => "Class XYZ does not conform to Protocol 'ObservableObject'.
Strange behaviour, because at old projects the code is working even though the build options are the same and other settings like iOS version in Target are the same.
There must be something chaged under the hood of XCode? I have to import Combine now, before I could write my class, e.g. CoreData Datamanager: ObservableObject only using CoreData.
Since macOS 26, including the latest 26.1, the menu bar icon does not show up for our app called Plover which is built with PySide6 (based on Qt 6) and runs via a relocatable python that is packaged into the app. The code is open source and can be found on GitHub. The latest release, including the notarized DMG, can be found here.
When running the .app via the command below, the menu bar icon does show up but the process that is running is python3.13 and not Plover:
/Applications/Plover.app/Contents/MacOS/Plover -l debug
When running the app by just clicking on the application icon, the process is Plover but the menu bar icon is not showing - also not in the settings (Menu Bar > Allow in the Menu Bar). Before macOS 26, the menu bar icon was always shown.
Some pointers to potentially relevant parts of our code:
shell script that builds the .app
Info.plist
plover_launcher.c
trayicon.py
This problem might be related to this thread, including the discussion around Qt not calling NSApplicationMain.
What I'm trying to figure out is whether this is a problem with macOS 26, Qt 6, PySide6, or our code.
Any pointers are highly appreciated!
Topic:
App & System Services
SubTopic:
Processes & Concurrency
In the header for workloop.h there is this note:
A dispatch workloop is a "subclass" of dispatch_queue_t which can be passed to all APIs accepting a dispatch queue, except for functions from the dispatch_sync() family. dispatch_async_and_wait() must be used for workloop objects. Functions from the dispatch_sync() family on queues targeting a workloop are still permitted but discouraged for performance reasons.
I have a couple questions related to this. First, I'd like to better understand what the alluded-to 'performance reasons' are that cause this pattern to be discouraged in the 'queues targeting a workloop' scenario. From further interrogation of the headers, I've found these explicit callouts regarding differences in the dispatch_sync and dispatch_async_and_wait API:
dispatch_sync:
Work items submitted to a queue with dispatch_sync() do not observe certain queue attributes of that queue when invoked (such as autorelease frequency and QOS class).
dispatch_async_and_wait:
Work items submitted to a queue with dispatch_async_and_wait() observe all queue attributes of that queue when invoked (inluding [sic] autorelease frequency or QOS class).
Additionally, dispatch_async_and_wait has a section of the headers devoted to 'Differences with dispatch_sync()', though I can't say I entirely follow the distinctions it attempts to draw.
Based on that, my best guess is that the 'performance reasons' are something about either QoS not being properly respected/observed or some thread context switching differences that can degrade performance, but I would appreciate insight from someone with more domain knowledge.
My second question is a bit more general – taking a step back, why exactly do these two API exist? It's not clear to me from the existing documentation I've found why I would/should prefer dispatch_sync over dispatch_async_and_wait (other than the aforementioned callout noting the former is unsupported on workloops). What is the motivation for preserving both these API vs deprecating dispatch_sync in favor of dispatch_async_and_wait (or functionally subsuming one with the other)?
Credit to Luna for originally posing/inspiring these questions.
Hi,
I'll explain my question through how whatsapp does it.
When the phone is locked then whatsapp routes call through apple's native callkit
When unlocked, pressing accept essentially redirects to whatsapp and then whatsapp handles the call from there.
However, this component of unlock detection is what I'm not able to find any info about.
Essentially,
how i do it is:
let isPhoneLocked = !UIApplication.shared.isProtectedDataAvailable
isProtectedDataAvailable == true → device is unlocked
isProtectedDataAvailable == false → device is locked
The problem is that if the phone has been recently unlocked, then protected data is still available on the phone even after the lock for the next 10-40 seconds. So theres a false positive.
I want there to be a foolproof and robust way to do this. And I'm not entirely sure how
Hi everyone,
I’m trying to register fonts system-wide using CTFontManagerRegisterFontURLs with the .persistent scope. The fonts are delivered through Apple-Hosted Background Assets (since On-Demand Resources are deprecated).
Process-level registration works perfectly, but persistent registration triggers a system “Install Fonts” prompt, and tapping Install causes the app to crash immediately.
I’m wondering if anyone has successfully used Apple-Hosted Background Assets to provide persistent, system-wide installable fonts, or if this is a current OS limitation/bug.
What I Expect
Fonts delivered through Apple-Hosted Background Assets should be eligible for system-wide installation
Tap “Install” should install fonts into Settings → Fonts just like app-bundled or ODR fonts
App should not crash
Why This Matters
According to:
WWDC 2019: Font Management and Text Scaling
Developers can build font provider apps that install fonts system-wide, using bundled or On-Demand Resources.
WWDC 2025: Discover Apple-Hosted Background Assets
On-Demand Resources are deprecated, and AHBAs are the modern replacement.
Therefore, persistent font installation via Apple-Hosted Background Assets appears to be the intended path moving forward.
Question
Is this a known limitation or bug in iOS?
Should .persistent font installation work with Apple-Hosted Background Assets?
Do we need additional entitlement, manifest configuration, or packaging rules?
Any guidance or confirmation from Apple engineers would be greatly appreciated.
Additional Info
I submitted a Feedback including a minimal reproducible sample project:
FB21109320
Topic:
App & System Services
SubTopic:
Processes & Concurrency
Tags:
Core Text
Background Assets
Typography
Concurrency
Currently I am trying to find a work around to fetch data from server and update user defaults when app is forced quit. Can anyone suggest for this ?
Hi there,
First thanks for all the work on BGContinuedProcessingTask! It looks really promising.
I have a question / issue around the behavior when a BGContinuedProcessingTask expires. Here is my setup.
I have an app who's responsible for uploading large files in the field (AKA wifi is not expected)
For a given file, it can likely fail due to network conditions
I'm using Multipart upload though so I can retry a file to pick up where it left off.
I use one taskIdentifier per file, and when the file fails, I can retry the task and have it continue where it left off (I am reusing the taskIdentifier here for retries, let me know if I shouldn't be doing that)
Here is the behavior I am seeing
I start an upload, it seems to be uploading normally
I turn on airplane mode to simulate expiration of the task
the task fails as expected after ~30 seconds, and I see the failure in my home screen.
I have callbacks in the task to put my app in the proper state on expiration / failure
I turn back on airplane mode and I retry the task, the way I do this is I do NOT re-register, I simply re-submit the task with the same TaskIdentifier.
What I would have expected is that the failure task is REPLACED with the new task and new progress. Instead what I see is TWO ContinuedBackgroundProcessingTasks, one in the failure state and one in progress.
My question is
How can I make retries reuse the same task notification item?
OR if that's not possible, how do I programmatically clear the task failure? I've tried cancelTask but that doesn't seem to clear it.