Core Bluetooth

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Communicate with Bluetooth 4.0 low energy devices using Core Bluetooth.

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BLE advertising/scanning communication broken on iPhone 17 — CBPeripheralManager + CBCentralManager workflow
Environment: iPhone 17 / iPhone 17 Pro (Apple N1 chip) iOS 26.x Xcode 26 Framework: Flutter app with native iOS BLE library (CoreBluetooth) We have a production IoT app that communicates with BLE nodes (Nordic, PIC, EnOcean peripherals) using an advertising/scanning-based protocol — not GATT connections. The app broadcasts commands via CBPeripheralManager (advertising service UUIDs) and receives responses by scanning with CBCentralManager (reading manufacturer data and service UUIDs from advertisement packets). This workflow has been reliable across all iPhone models from iPhone 8 through iPhone 16 Pro Max. On iPhone 17 devices, we are experiencing multiple failures in this workflow. Architecture: Sending commands: We use CBPeripheralManager.startAdvertising() with CBAdvertisementDataServiceUUIDsKey to broadcast a UUID-encoded command to nearby nodes. Receiving responses: We use CBCentralManager.scanForPeripherals(withServices: nil, options: [CBCentralManagerScanOptionAllowDuplicatesKey: true]) and filter responses in centralManager(_:didDiscover:advertisementData:rssi:) by matching CBAdvertisementDataServiceUUIDsKey or CBAdvertisementDataManufacturerDataKey against expected UUID masks. Communication pattern: Advertise a command → stop advertiser → start scanner → wait for matching response → process result. Typical timeout is 1.5 seconds per exchange. Issues observed on iPhone 17: peripheralManagerDidStartAdvertising behaviour change After calling CBPeripheralManager.startAdvertising(:), the delegate callback peripheralManagerDidStartAdvertising(:error:) either fires with errors that did not occur on previous hardware, or advertising does not appear to reach the peripheral nodes at all. The same advertising payload works immediately when tested on iPhone 15/16. Is the N1 chip's Bluetooth 6 stack handling CBAdvertisementDataServiceUUIDsKey advertising differently? Are there new constraints on advertising payload size or format? Scanner returning fewer/no results with withServices: nil Our scanner uses scanForPeripherals(withServices: nil) because we need to read manufacturer data from advertisement packets and filter using a custom UUID mask. On iPhone 17, we observe significantly fewer didDiscover callbacks compared to iPhone 15/16 in the same physical environment, with the same nodes advertising. We understand that passing service UUIDs in withServices: is recommended, but our protocol requires reading raw manufacturer data bytes that aren't associated with a single service UUID — we use mask-based matching (e.g., filter mask 11110000-0000-0000-0000-000000000000 against scan results). Has the N1 chip changed the rate or filtering behaviour of unfiltered BLE scans? Is there a new throttling mechanism? Background scanning stops immediately When the app moves to background, scanning appears to stop entirely on iPhone 17 — even with bluetooth-central in UIBackgroundModes. On iPhone 16, background scanning continued (at reduced intervals) and delivered results for peripherals advertising filtered service UUIDs. Aggressive session termination on app backgrounding Our advertise-then-scan sequences (typically 1.5s round-trip) are being interrupted when the user briefly switches apps. The CBPeripheralManager stops advertising and the CBCentralManager stops scanning, causing timeout errors. This was not observed on previous iPhone models with the same iOS background mode configuration. Questions for Apple: Are there documented changes to CoreBluetooth behaviour on the N1 Bluetooth 6 chip that affect advertising-based (non-GATT) communication patterns? Has the scan response rate for scanForPeripherals(withServices: nil) been intentionally reduced on iPhone 17? Is CBCentralManagerOptionRestoreIdentifierKey now required for reliable background scanning on iPhone 17, or is this a known regression? Are there new advertising payload constraints (size, format, interval) that we should be aware of for the N1 chip? What we've tried: Added NSBluetoothAlwaysUsageDescription and NSBluetoothWhileInUseUsageDescription to Info.plist Confirmed Bluetooth permissions are granted Tested with identical BLE nodes that work on iPhone 15/16 Verified CBManagerState.poweredOn before all operations Any guidance or known workarounds would be greatly appreciated. Happy to provide sysdiagnose logs or a minimal reproducible sample project.
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379
Feb ’26
CBCentralManager State Changes to PoweredOff After Using ASK for Accessory Setup
We are observing some unexpected behavior in our app when using ASK. Our app is able to successfully discover and set up an accessory via ASK. After the setup completes, the connection to the accessory is managed through CBCentralManager and works as expected. However, when we attempt to discover another accessory afterward, the picker is shown and indicates that accessory discovery is in progress. After approximately 10 seconds, the CBCentralManager delegate reports the Bluetooth state as poweredOff. Once this happens, the state never transitions back to poweredOn. At this point, the only way to reconnect to the device or continue discovery is to relaunch the app. We are wondering if anyone else has encountered similar behavior, or if this is a known or documented limitation/behavior when using ASK in combination with CBCentralManager.
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617
Feb ’26
bluetooth control
I am learning about endpoint security and other system extensions, while I was handling ES_EVENT_TYPE_AUTH_IOKIT_OPEN event I realized that I cannot auth deny any bluetooth events. I tried to deny any open or execute events related to com.apple.bluetoothd but it did not work. I searched google and found out that I can use CoreBluetooth to control bluetooth. But when I get connected to bluetooth keyboard or mouse, didConnectPeripheral dose not get called or when I call [central cancelPeripheralConnection:peripheral] disconnection never happens. Is there any recommendation for handling or controlling events related to bluetooth connection?
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1k
Feb ’26
BLE Scanning
iOS BLE Background Scanning Stops After Few Minutes to Hours Hi everyone, I'm developing a Flutter app using flutter_blue_plus that needs continuous BLE scanning in both foreground and background. Foreground scanning works perfectly, but background scanning stops after a few minutes (sometimes 1-2 hours). Current Implementation (iOS) Foreground Mode: Scans for 10 seconds with all target service UUIDs Batches and submits results every 10 seconds Works reliably ✅ Background Mode: Rotates through service UUIDs in batches of 7 Uses 1-minute batch intervals Maintains active location streaming (Geolocator.getPositionStream) Switches modes via AppLifecycleState observer // Background scanning setup await FlutterBluePlus.startScan( withServices: serviceUuids, // Batch of 7 UUIDs continuousUpdates: true, ); // Location streaming (attempt to keep app alive) LocationSettings( accuracy: LocationAccuracy.bestForNavigation, distanceFilter: 0, ); Lifecycle Management: AppLifecycleState.paused -> Start background mode AppLifecycleState.resumed -> Start foreground mode Questions: Is there a documented maximum duration for iOS background BLE scanning? My scanning stops inconsistently (few minutes to 2 hours). Does iOS require specific Background Modes beyond location updates to maintain BLE scanning? I have location streaming active but scanning still stops. Are there undocumented limitations when scanning with service UUIDs in background that might cause termination? Should I be using CoreBluetooth's state preservation/restoration instead of continuous scanning? Info.plist Configuration: <key>UIBackgroundModes</key> <array> <string>bluetooth-central</string> <string>location</string> </array> Additional Context: Total service UUIDs: ~20-50 (varies by company) Scanning in batches of 7 to work around potential limitations Android version works fine with foreground service Location permission: Always iOS 14+ target Any insights on iOS BLE background limitations or best practices would be greatly appreciated. Thanks!
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Feb ’26
iOS App never gets Bluetooth connection
I am developing an iOS App for a Bluetooth peripheral using SwiftUI with Swift 5 or 6. I have a few past attempts that got so far (connected to a peripheral), and some downloaded examples that connect to peripherals. Lately (last month or so), my current attempt never gets BleManager to start, and every attempt ends at my View that says 'please enable Bluetooth'. The Xcode console is totally blank with no print outputs. Coding Assistant suggested the init() in my @main structure could contain print("App initializing"), but even that never prints. Coding Assistant suggests: "• Open your project's Info.plist in Xcode. • Make sure UIApplicationSceneManifest is present and configured for SwiftUI, not referencing any storyboard. • Ensure UIMainStoryboardFile is not present (or blank)." but there is no info.plist because it is no longer required. Downloaded sample code runs and connects to peripherals, so Bluetooth is working on my iPhone and the Bluetooth device is accessible. My older attempts used to work, but now have the same problem. All attempts have "Enable Bluetooth to connect to Device" in the Privacy - Bluetooth Info.plist setting. Something is fundamentally wrong with many different code attempts. I have searched all the various settings for mention of SwiftUI or Storyboard, but not found them in working or failing projects. The downloaded code which works has minimum deployment iOS 14.0 and Swift Compiler Language Version Swift 5. My latest code attempt has minimum deployment iOS 16 and Swift 5. All code is target device iPhone (I am testing on iPhone 16e running iOS 26.2.1) and developing with Xcode 26.2 on MacBook Air M1 running the latest Tahoe. I do a Clean Build Folder before every test, and have tried re-starting both Mac and iPhone. How can my coding fail so spectacularly?
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Feb ’26
Unexpected CoreBluetooth background suspension without active location updates
I am implementing BLE scanning and connection using CoreBluetooth in a Flutter application with native iOS Swift code. BLE scanning and connection work correctly in the foreground and for a short time after the app is sent to the background. However, after some time in the background, BLE scanning stops and the device is no longer discovered. The app appears to be suspended by iOS. Key Observation: When location services are actively in use (navigation arrow visible in the iOS status bar), BLE scanning and reconnection work reliably in the background. When location services are not actively running, BLE scanning stops in the background even though the app has “Always Allow” location permission. Expected Result BLE scanning and connection should continue to function in the background using the Bluetooth LE background mode, without relying on active location updates. Actual Result BLE scanning starts successfully App enters background After some time, scanning stops Device is no longer discovered BLE works again only if location services are actively running BLE Connection Behavior One-time scan connects successfully to a BLE medical device App is sent to background Existing connection does not disconnect However, new scans or reconnections fail once the app is suspended Relevant Native iOS Code (AppDelegate) import Flutter import UIKit import CoreBluetooth @main @objc class AppDelegate: FlutterAppDelegate { private var backgroundTaskID: UIBackgroundTaskIdentifier = .invalid override func application( _ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]? ) -> Bool { GeneratedPluginRegistrant.register(with: self) if let identifiers = launchOptions?[UIApplication.LaunchOptionsKey.bluetoothCentrals] as? [String] { print("App relaunched for BLE state restoration: \(identifiers)") } NotificationCenter.default.addObserver( self, selector: #selector(appDidEnterBackground), name: UIApplication.didEnterBackgroundNotification, object: nil ) return super.application(application, didFinishLaunchingWithOptions: launchOptions) } @objc private func appDidEnterBackground() { backgroundTaskID = UIApplication.shared.beginBackgroundTask { self.endBackgroundTask() } } private func endBackgroundTask() { if backgroundTaskID != .invalid { UIApplication.shared.endBackgroundTask(backgroundTaskID) backgroundTaskID = .invalid } } } Questions for DTS: Is it expected behavior that CoreBluetooth background scanning effectively stops once the app is suspended, even when the Bluetooth LE background mode is enabled? Why does BLE background scanning appear to work reliably only when location services are actively running? Is iOS internally associating BLE background execution with active location updates? For continuous BLE reconnection (medical device use case), is the recommended approach to rely solely on CoreBluetooth state restoration instead of continuous background scanning? Is it considered best practice to avoid long-running BLE scans in the background and instead wait for system-delivered BLE events? Additional Notes Issue is reproducible on real devices Not using private APIs or unsupported background execution methods Objective is to follow Apple-recommended, App Store–compliant behavior
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507
Feb ’26
Background scanning for Bluetooth advertisements with LiveActivities on ios26
Hi, I am trying to understand if I am able to get bluetooth scanning for advertisements (no service UUID) when the app is moved into the background and the screen goes to sleep. I am using swift on ios26.2 with a bluetooth class that uses the standard centralManager.scanForPeripherals to listen for particular Beacons. Testing on a real iPhone 15 this works fine whilst in the foreground, and also when on the lock screen. I am trying to get this to continue working in the background when the black screen sleep mode is on. I have the bluetooth 'Uses Bluetooth LE accessories' in the background modes (as well as Audio, Airplay..) and the necessary Bluetooth peripheral usage description, bluetooth always usage descriptions in info.plist. I launch a LiveActivity whilst the app is in the foreground and bluetooth has started scanning. From my understanding of core bluetooth with ios26 the LiveActivity should allow the scan to continue (without service UUIds and aggressive throttling) whilst the app is in the background. Well this seems to work fine.. if I press the side button the phone goes to the Lock Screen, and whilst on the Lock Screen the bluetooth is scanning fine and receiving beacon data. Similarly if the app is sent to the background behind a different foreground app it also works. As soon as the screen goes to sleep however (after only a few seconds of inactivity on the Lock Screen) then all bluetooth scanning stops. If I click back on the screen and bring the Lock Screen up, then scanning resumes again. Now is it possible to continue the scanning whilst the phone is in sleep mode (i.e. black screen)? Are there any additional acceptable steps to make the bluetooth scanning continue when the screen has gone to sleep. Or is it part of the design with core bluetooth that the 'continues in the background' feature only applies to the lock screen and when other active apps are brought to the foreground on an open phone. I want to understand the limitations of what can be achieved so I am not chasing unachievable objectives. Thanks
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Feb ’26
CoreBluetooth Advertiser role CBPeripheralManager didSubscribeToCharacteristic: not getting invoked on iPhone 17 Air/Pro (iOS 26.1+)
When using CBPeripheralManager in the peripheral role on iPhone 17 series devices (iPhone 17 Air, iPhone 17 Pro) running iOS 26.1 and above, the delegate method peripheralManager:central:didSubscribeToCharacteristic: is never called when a third-party BLE central device attempts to connect and subscribe to a characteristic. This functionality works correctly on all previous iPhone models and iOS versions. (This worked previously for the same iPhone 17 Air/Pro when running iOS 26.0.1.)
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Feb ’26
Inter-app Communication with Third Party SDK
I’ve built an app that connects via Bluetooth to a device. The device sends up, down, left and right commands. I want to build an SDK for other third party developers to use so that whenever a third party app with the SDK opens, if we press a button on the device, my app which captures the button press should be able to forward the event to the third party app. I want to achieve this with the lowest latency possible so that I can enable a variety of use cases like simple games and interactions within other apps. What would be the best way for me to achieve this as part of my SDK and my app?
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Feb ’26
Pair iOS Central with MacOS Peripheral for encrypted characteristic
Is this even possible? Instead of any pairing dialog appearing, my central code get the "Authentication is insufficient" error when reading the characteristic. My peripheral (in the macOS app) code uses the .notifyEncryptionRequired property and uses .readEncryptionRequired and .writeEncryptionRequired permissions. No descriptors are set, but I think they get added automatically since this characteristic notifies. 2900 and 2902 descriptors are set by the peripheral/CoreBluetooth. If the Mac and iPhone are using the same Apple ID does that affect pairing?
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90
Feb ’26
BLE Advertising in Background
For our research study, it is essential that the app can advertise BLE packets even when the app is no longer in the foreground (for example, when it is in the app switcher / recents state). Is it supported to advertise BLE packets while the app is in the background or recents state? If so, what are the specific requirements or limitations we should be aware of (background modes, payload size, timing, etc.)? Are there any constraints that would prevent consistent BLE advertising for research use cases?
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Feb ’26
CoreBluetooth connection never starts
I'm scanning for peripherals, and keep references to multiple CBUUIDs - one for each peripheral. I then start a connection to the peripheral. I never get a callback to say the connection succeeded, failed, or disconnected. I have a Mini-Moreph Bluetooth sniffer. The sniffer shows that the iPhone never tried to connect to any of the peripherals. The iPhone HCI logs show that a create connection request was sent, but a cancel connection request was sent 0.018 seconds later. No feedback was given to my application through CoreBluetooth. I've filed this through Feedback Assistant, but expect nothing will come of the report.
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Jan ’26
Requesting guidance on long-running background BLE control triggered by server-side events
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.
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Jan ’26
BLE audio packet loss on iPhone 17 (Bluetooth 6 / N1) in real-time streaming
Hello Apple Bluetooth team, We are developing a real-time call translation system that streams raw PCM audio over BLE between iPhone and custom earbuds. This works reliably on iPhone 14 / 15 / 16, but on iPhone 17 (Bluetooth 6, N1 chip) we see severe and repeatable BLE packet loss, affecting both microphone uplink and TTS downlink. Our audio stream 16 kHz, 16-bit mono PCM 20 ms frames (~640 bytes) continuous bidirectional BLE streaming What happens on iPhone 17 BLE packets are frequently dropped entire audio frames are missing results in ASR gaps and broken TTS playback occurs even with strong RSSI and no RF interference Same firmware, same BLE protocol, same MTU and connection interval work normally on older iPhones. Questions We would like to know: Did Bluetooth 6 / N1 change BLE throughput, buffering, or scheduling? Are there new limits on sustained notify / write-without-response traffic? Is BLE audio now arbitrated differently against Wi-Fi / A2DP on iPhone 17? Is BLE still expected to support low-latency continuous audio streaming on iPhone 17, or is this no longer a safe assumption? Any guidance or new best practices would be greatly appreciated. Best regards, Valenti Zhang
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Jan ’26
peripheralIsReadyToSendWriteWithoutResponse not be invoked when App into the background
I'm developing an App, a function is through the bluetooth firmware upgrade. there is a problem now. when I send data via bluetooth, App into the background, the data sent to immediately stop, peripheralIsReadyToSendWriteWithoutResponse will not be invoked, At the same time canSendWriteWithoutResponse always returns false. When I open the App again, peripheralIsReadyToSendWriteWithoutResponse still will not be invoked, canSendWriteWithoutResponse or returns false. I have set Acts as a Bluetooth LE accessory and Uses Bluetooth LE accessories. Is there a good way to send data to the device when my App goes into the background?
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383
Jan ’26
visionOS Bluetooth LE limited to 2 connections?
Hello, Is there a 2-device limit for CoreBluetooth on visionOS 2.1? My app connects to 4 BLE peripherals on iOS but fails at the 3rd device on Vision Pro. The 3rd call to centralManager.connect() is successful and the peripheral enters .connecting state, but didConnect never fires and it stays in .connecting forever. No errors reported. First 2 devices work perfectly. Same code on iOS connects all 4. Has anyone else had this problem? Is there any documentation I can refer to that states something like this? Environment: visionOS 2.1, CoreBluetooth, Apple Vision Pro. My BLE Peripherals are running on nRF52840.
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Jan ’26
BLE advertising/scanning communication broken on iPhone 17 — CBPeripheralManager + CBCentralManager workflow
Environment: iPhone 17 / iPhone 17 Pro (Apple N1 chip) iOS 26.x Xcode 26 Framework: Flutter app with native iOS BLE library (CoreBluetooth) We have a production IoT app that communicates with BLE nodes (Nordic, PIC, EnOcean peripherals) using an advertising/scanning-based protocol — not GATT connections. The app broadcasts commands via CBPeripheralManager (advertising service UUIDs) and receives responses by scanning with CBCentralManager (reading manufacturer data and service UUIDs from advertisement packets). This workflow has been reliable across all iPhone models from iPhone 8 through iPhone 16 Pro Max. On iPhone 17 devices, we are experiencing multiple failures in this workflow. Architecture: Sending commands: We use CBPeripheralManager.startAdvertising() with CBAdvertisementDataServiceUUIDsKey to broadcast a UUID-encoded command to nearby nodes. Receiving responses: We use CBCentralManager.scanForPeripherals(withServices: nil, options: [CBCentralManagerScanOptionAllowDuplicatesKey: true]) and filter responses in centralManager(_:didDiscover:advertisementData:rssi:) by matching CBAdvertisementDataServiceUUIDsKey or CBAdvertisementDataManufacturerDataKey against expected UUID masks. Communication pattern: Advertise a command → stop advertiser → start scanner → wait for matching response → process result. Typical timeout is 1.5 seconds per exchange. Issues observed on iPhone 17: peripheralManagerDidStartAdvertising behaviour change After calling CBPeripheralManager.startAdvertising(:), the delegate callback peripheralManagerDidStartAdvertising(:error:) either fires with errors that did not occur on previous hardware, or advertising does not appear to reach the peripheral nodes at all. The same advertising payload works immediately when tested on iPhone 15/16. Is the N1 chip's Bluetooth 6 stack handling CBAdvertisementDataServiceUUIDsKey advertising differently? Are there new constraints on advertising payload size or format? Scanner returning fewer/no results with withServices: nil Our scanner uses scanForPeripherals(withServices: nil) because we need to read manufacturer data from advertisement packets and filter using a custom UUID mask. On iPhone 17, we observe significantly fewer didDiscover callbacks compared to iPhone 15/16 in the same physical environment, with the same nodes advertising. We understand that passing service UUIDs in withServices: is recommended, but our protocol requires reading raw manufacturer data bytes that aren't associated with a single service UUID — we use mask-based matching (e.g., filter mask 11110000-0000-0000-0000-000000000000 against scan results). Has the N1 chip changed the rate or filtering behaviour of unfiltered BLE scans? Is there a new throttling mechanism? Background scanning stops immediately When the app moves to background, scanning appears to stop entirely on iPhone 17 — even with bluetooth-central in UIBackgroundModes. On iPhone 16, background scanning continued (at reduced intervals) and delivered results for peripherals advertising filtered service UUIDs. Aggressive session termination on app backgrounding Our advertise-then-scan sequences (typically 1.5s round-trip) are being interrupted when the user briefly switches apps. The CBPeripheralManager stops advertising and the CBCentralManager stops scanning, causing timeout errors. This was not observed on previous iPhone models with the same iOS background mode configuration. Questions for Apple: Are there documented changes to CoreBluetooth behaviour on the N1 Bluetooth 6 chip that affect advertising-based (non-GATT) communication patterns? Has the scan response rate for scanForPeripherals(withServices: nil) been intentionally reduced on iPhone 17? Is CBCentralManagerOptionRestoreIdentifierKey now required for reliable background scanning on iPhone 17, or is this a known regression? Are there new advertising payload constraints (size, format, interval) that we should be aware of for the N1 chip? What we've tried: Added NSBluetoothAlwaysUsageDescription and NSBluetoothWhileInUseUsageDescription to Info.plist Confirmed Bluetooth permissions are granted Tested with identical BLE nodes that work on iPhone 15/16 Verified CBManagerState.poweredOn before all operations Any guidance or known workarounds would be greatly appreciated. Happy to provide sysdiagnose logs or a minimal reproducible sample project.
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3
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379
Activity
Feb ’26
CBCentralManager State Changes to PoweredOff After Using ASK for Accessory Setup
We are observing some unexpected behavior in our app when using ASK. Our app is able to successfully discover and set up an accessory via ASK. After the setup completes, the connection to the accessory is managed through CBCentralManager and works as expected. However, when we attempt to discover another accessory afterward, the picker is shown and indicates that accessory discovery is in progress. After approximately 10 seconds, the CBCentralManager delegate reports the Bluetooth state as poweredOff. Once this happens, the state never transitions back to poweredOn. At this point, the only way to reconnect to the device or continue discovery is to relaunch the app. We are wondering if anyone else has encountered similar behavior, or if this is a known or documented limitation/behavior when using ASK in combination with CBCentralManager.
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5
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3
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617
Activity
Feb ’26
bluetooth control
I am learning about endpoint security and other system extensions, while I was handling ES_EVENT_TYPE_AUTH_IOKIT_OPEN event I realized that I cannot auth deny any bluetooth events. I tried to deny any open or execute events related to com.apple.bluetoothd but it did not work. I searched google and found out that I can use CoreBluetooth to control bluetooth. But when I get connected to bluetooth keyboard or mouse, didConnectPeripheral dose not get called or when I call [central cancelPeripheralConnection:peripheral] disconnection never happens. Is there any recommendation for handling or controlling events related to bluetooth connection?
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3
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0
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1k
Activity
Feb ’26
BLE Scanning
iOS BLE Background Scanning Stops After Few Minutes to Hours Hi everyone, I'm developing a Flutter app using flutter_blue_plus that needs continuous BLE scanning in both foreground and background. Foreground scanning works perfectly, but background scanning stops after a few minutes (sometimes 1-2 hours). Current Implementation (iOS) Foreground Mode: Scans for 10 seconds with all target service UUIDs Batches and submits results every 10 seconds Works reliably ✅ Background Mode: Rotates through service UUIDs in batches of 7 Uses 1-minute batch intervals Maintains active location streaming (Geolocator.getPositionStream) Switches modes via AppLifecycleState observer // Background scanning setup await FlutterBluePlus.startScan( withServices: serviceUuids, // Batch of 7 UUIDs continuousUpdates: true, ); // Location streaming (attempt to keep app alive) LocationSettings( accuracy: LocationAccuracy.bestForNavigation, distanceFilter: 0, ); Lifecycle Management: AppLifecycleState.paused -> Start background mode AppLifecycleState.resumed -> Start foreground mode Questions: Is there a documented maximum duration for iOS background BLE scanning? My scanning stops inconsistently (few minutes to 2 hours). Does iOS require specific Background Modes beyond location updates to maintain BLE scanning? I have location streaming active but scanning still stops. Are there undocumented limitations when scanning with service UUIDs in background that might cause termination? Should I be using CoreBluetooth's state preservation/restoration instead of continuous scanning? Info.plist Configuration: <key>UIBackgroundModes</key> <array> <string>bluetooth-central</string> <string>location</string> </array> Additional Context: Total service UUIDs: ~20-50 (varies by company) Scanning in batches of 7 to work around potential limitations Android version works fine with foreground service Location permission: Always iOS 14+ target Any insights on iOS BLE background limitations or best practices would be greatly appreciated. Thanks!
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1
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0
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132
Activity
Feb ’26
iOS App never gets Bluetooth connection
I am developing an iOS App for a Bluetooth peripheral using SwiftUI with Swift 5 or 6. I have a few past attempts that got so far (connected to a peripheral), and some downloaded examples that connect to peripherals. Lately (last month or so), my current attempt never gets BleManager to start, and every attempt ends at my View that says 'please enable Bluetooth'. The Xcode console is totally blank with no print outputs. Coding Assistant suggested the init() in my @main structure could contain print("App initializing"), but even that never prints. Coding Assistant suggests: "• Open your project's Info.plist in Xcode. • Make sure UIApplicationSceneManifest is present and configured for SwiftUI, not referencing any storyboard. • Ensure UIMainStoryboardFile is not present (or blank)." but there is no info.plist because it is no longer required. Downloaded sample code runs and connects to peripherals, so Bluetooth is working on my iPhone and the Bluetooth device is accessible. My older attempts used to work, but now have the same problem. All attempts have "Enable Bluetooth to connect to Device" in the Privacy - Bluetooth Info.plist setting. Something is fundamentally wrong with many different code attempts. I have searched all the various settings for mention of SwiftUI or Storyboard, but not found them in working or failing projects. The downloaded code which works has minimum deployment iOS 14.0 and Swift Compiler Language Version Swift 5. My latest code attempt has minimum deployment iOS 16 and Swift 5. All code is target device iPhone (I am testing on iPhone 16e running iOS 26.2.1) and developing with Xcode 26.2 on MacBook Air M1 running the latest Tahoe. I do a Clean Build Folder before every test, and have tried re-starting both Mac and iPhone. How can my coding fail so spectacularly?
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2
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0
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168
Activity
Feb ’26
Unexpected CoreBluetooth background suspension without active location updates
I am implementing BLE scanning and connection using CoreBluetooth in a Flutter application with native iOS Swift code. BLE scanning and connection work correctly in the foreground and for a short time after the app is sent to the background. However, after some time in the background, BLE scanning stops and the device is no longer discovered. The app appears to be suspended by iOS. Key Observation: When location services are actively in use (navigation arrow visible in the iOS status bar), BLE scanning and reconnection work reliably in the background. When location services are not actively running, BLE scanning stops in the background even though the app has “Always Allow” location permission. Expected Result BLE scanning and connection should continue to function in the background using the Bluetooth LE background mode, without relying on active location updates. Actual Result BLE scanning starts successfully App enters background After some time, scanning stops Device is no longer discovered BLE works again only if location services are actively running BLE Connection Behavior One-time scan connects successfully to a BLE medical device App is sent to background Existing connection does not disconnect However, new scans or reconnections fail once the app is suspended Relevant Native iOS Code (AppDelegate) import Flutter import UIKit import CoreBluetooth @main @objc class AppDelegate: FlutterAppDelegate { private var backgroundTaskID: UIBackgroundTaskIdentifier = .invalid override func application( _ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]? ) -> Bool { GeneratedPluginRegistrant.register(with: self) if let identifiers = launchOptions?[UIApplication.LaunchOptionsKey.bluetoothCentrals] as? [String] { print("App relaunched for BLE state restoration: \(identifiers)") } NotificationCenter.default.addObserver( self, selector: #selector(appDidEnterBackground), name: UIApplication.didEnterBackgroundNotification, object: nil ) return super.application(application, didFinishLaunchingWithOptions: launchOptions) } @objc private func appDidEnterBackground() { backgroundTaskID = UIApplication.shared.beginBackgroundTask { self.endBackgroundTask() } } private func endBackgroundTask() { if backgroundTaskID != .invalid { UIApplication.shared.endBackgroundTask(backgroundTaskID) backgroundTaskID = .invalid } } } Questions for DTS: Is it expected behavior that CoreBluetooth background scanning effectively stops once the app is suspended, even when the Bluetooth LE background mode is enabled? Why does BLE background scanning appear to work reliably only when location services are actively running? Is iOS internally associating BLE background execution with active location updates? For continuous BLE reconnection (medical device use case), is the recommended approach to rely solely on CoreBluetooth state restoration instead of continuous background scanning? Is it considered best practice to avoid long-running BLE scans in the background and instead wait for system-delivered BLE events? Additional Notes Issue is reproducible on real devices Not using private APIs or unsupported background execution methods Objective is to follow Apple-recommended, App Store–compliant behavior
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2
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0
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507
Activity
Feb ’26
Background scanning for Bluetooth advertisements with LiveActivities on ios26
Hi, I am trying to understand if I am able to get bluetooth scanning for advertisements (no service UUID) when the app is moved into the background and the screen goes to sleep. I am using swift on ios26.2 with a bluetooth class that uses the standard centralManager.scanForPeripherals to listen for particular Beacons. Testing on a real iPhone 15 this works fine whilst in the foreground, and also when on the lock screen. I am trying to get this to continue working in the background when the black screen sleep mode is on. I have the bluetooth 'Uses Bluetooth LE accessories' in the background modes (as well as Audio, Airplay..) and the necessary Bluetooth peripheral usage description, bluetooth always usage descriptions in info.plist. I launch a LiveActivity whilst the app is in the foreground and bluetooth has started scanning. From my understanding of core bluetooth with ios26 the LiveActivity should allow the scan to continue (without service UUIds and aggressive throttling) whilst the app is in the background. Well this seems to work fine.. if I press the side button the phone goes to the Lock Screen, and whilst on the Lock Screen the bluetooth is scanning fine and receiving beacon data. Similarly if the app is sent to the background behind a different foreground app it also works. As soon as the screen goes to sleep however (after only a few seconds of inactivity on the Lock Screen) then all bluetooth scanning stops. If I click back on the screen and bring the Lock Screen up, then scanning resumes again. Now is it possible to continue the scanning whilst the phone is in sleep mode (i.e. black screen)? Are there any additional acceptable steps to make the bluetooth scanning continue when the screen has gone to sleep. Or is it part of the design with core bluetooth that the 'continues in the background' feature only applies to the lock screen and when other active apps are brought to the foreground on an open phone. I want to understand the limitations of what can be achieved so I am not chasing unachievable objectives. Thanks
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1
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145
Activity
Feb ’26
CoreBluetooth Advertiser role CBPeripheralManager didSubscribeToCharacteristic: not getting invoked on iPhone 17 Air/Pro (iOS 26.1+)
When using CBPeripheralManager in the peripheral role on iPhone 17 series devices (iPhone 17 Air, iPhone 17 Pro) running iOS 26.1 and above, the delegate method peripheralManager:central:didSubscribeToCharacteristic: is never called when a third-party BLE central device attempts to connect and subscribe to a characteristic. This functionality works correctly on all previous iPhone models and iOS versions. (This worked previously for the same iPhone 17 Air/Pro when running iOS 26.0.1.)
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3
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198
Activity
Feb ’26
Inter-app Communication with Third Party SDK
I’ve built an app that connects via Bluetooth to a device. The device sends up, down, left and right commands. I want to build an SDK for other third party developers to use so that whenever a third party app with the SDK opens, if we press a button on the device, my app which captures the button press should be able to forward the event to the third party app. I want to achieve this with the lowest latency possible so that I can enable a variety of use cases like simple games and interactions within other apps. What would be the best way for me to achieve this as part of my SDK and my app?
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3
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247
Activity
Feb ’26
Pair iOS Central with MacOS Peripheral for encrypted characteristic
Is this even possible? Instead of any pairing dialog appearing, my central code get the "Authentication is insufficient" error when reading the characteristic. My peripheral (in the macOS app) code uses the .notifyEncryptionRequired property and uses .readEncryptionRequired and .writeEncryptionRequired permissions. No descriptors are set, but I think they get added automatically since this characteristic notifies. 2900 and 2902 descriptors are set by the peripheral/CoreBluetooth. If the Mac and iPhone are using the same Apple ID does that affect pairing?
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0
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90
Activity
Feb ’26
Core Bluetooth on tvOS
How does core bluetooth work on tvOS? Is it available for use? Any docs would be helpful?
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2
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452
Activity
Feb ’26
BLE Advertising in Background
For our research study, it is essential that the app can advertise BLE packets even when the app is no longer in the foreground (for example, when it is in the app switcher / recents state). Is it supported to advertise BLE packets while the app is in the background or recents state? If so, what are the specific requirements or limitations we should be aware of (background modes, payload size, timing, etc.)? Are there any constraints that would prevent consistent BLE advertising for research use cases?
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2
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0
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341
Activity
Feb ’26
iPhone17 bluetooth background scanning issue
Recently, I've noticed that background Bluetooth scanning stops when I move an app to the background on an iPhone 17 device with Bluetooth 6. I'm curious about a solution. Background Bluetooth scanning doesn't stop on devices older than iOS 26, or on devices that were updated from an iPhone 17 or earlier to iOS 26.
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10
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640
Activity
Feb ’26
CoreBluetooth connection never starts
I'm scanning for peripherals, and keep references to multiple CBUUIDs - one for each peripheral. I then start a connection to the peripheral. I never get a callback to say the connection succeeded, failed, or disconnected. I have a Mini-Moreph Bluetooth sniffer. The sniffer shows that the iPhone never tried to connect to any of the peripherals. The iPhone HCI logs show that a create connection request was sent, but a cancel connection request was sent 0.018 seconds later. No feedback was given to my application through CoreBluetooth. I've filed this through Feedback Assistant, but expect nothing will come of the report.
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6
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358
Activity
Jan ’26
Requesting guidance on long-running background BLE control triggered by server-side events
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.
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0
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160
Activity
Jan ’26
Roadmap for Coded PHY support in CoreBluetooth
I am looking to extend the range for a device and the only option from a Bluetooth perspective is Coded PHY but I have not heard of any intent to support it from Apple. Does Apple intend to support Coded PHY and if so what is the roadmap?
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3
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2
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361
Activity
Jan ’26
Missing Bluetooth background mode
I built an iOS app and debugged it using my iPhone 11. It works fine. My app uses Bluetooth because the physical data logger reads data via Bluetooth. I published it to the Apple store. After installing it on the iPhone 13 pro. The app works, but the device is not selected.
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0
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131
Activity
Jan ’26
BLE audio packet loss on iPhone 17 (Bluetooth 6 / N1) in real-time streaming
Hello Apple Bluetooth team, We are developing a real-time call translation system that streams raw PCM audio over BLE between iPhone and custom earbuds. This works reliably on iPhone 14 / 15 / 16, but on iPhone 17 (Bluetooth 6, N1 chip) we see severe and repeatable BLE packet loss, affecting both microphone uplink and TTS downlink. Our audio stream 16 kHz, 16-bit mono PCM 20 ms frames (~640 bytes) continuous bidirectional BLE streaming What happens on iPhone 17 BLE packets are frequently dropped entire audio frames are missing results in ASR gaps and broken TTS playback occurs even with strong RSSI and no RF interference Same firmware, same BLE protocol, same MTU and connection interval work normally on older iPhones. Questions We would like to know: Did Bluetooth 6 / N1 change BLE throughput, buffering, or scheduling? Are there new limits on sustained notify / write-without-response traffic? Is BLE audio now arbitrated differently against Wi-Fi / A2DP on iPhone 17? Is BLE still expected to support low-latency continuous audio streaming on iPhone 17, or is this no longer a safe assumption? Any guidance or new best practices would be greatly appreciated. Best regards, Valenti Zhang
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2
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1
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285
Activity
Jan ’26
peripheralIsReadyToSendWriteWithoutResponse not be invoked when App into the background
I'm developing an App, a function is through the bluetooth firmware upgrade. there is a problem now. when I send data via bluetooth, App into the background, the data sent to immediately stop, peripheralIsReadyToSendWriteWithoutResponse will not be invoked, At the same time canSendWriteWithoutResponse always returns false. When I open the App again, peripheralIsReadyToSendWriteWithoutResponse still will not be invoked, canSendWriteWithoutResponse or returns false. I have set Acts as a Bluetooth LE accessory and Uses Bluetooth LE accessories. Is there a good way to send data to the device when my App goes into the background?
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0
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383
Activity
Jan ’26
visionOS Bluetooth LE limited to 2 connections?
Hello, Is there a 2-device limit for CoreBluetooth on visionOS 2.1? My app connects to 4 BLE peripherals on iOS but fails at the 3rd device on Vision Pro. The 3rd call to centralManager.connect() is successful and the peripheral enters .connecting state, but didConnect never fires and it stays in .connecting forever. No errors reported. First 2 devices work perfectly. Same code on iOS connects all 4. Has anyone else had this problem? Is there any documentation I can refer to that states something like this? Environment: visionOS 2.1, CoreBluetooth, Apple Vision Pro. My BLE Peripherals are running on nRF52840.
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1
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97
Activity
Jan ’26