In my app, a crash occurs only on iOS 17.xx versions when I establish a BLE connection to a peripheral, scan wifi networks and connect to one of them via BLE.
private func writeData(writingMode: String) { guard let discoveredPeripheral = discoveredPeripheral, let transferCharacteristic = transferCharacteristic else { return } // check to see if number of iterations completed and peripheral can accept more data let mtu = discoveredPeripheral.maximumWriteValueLength (for: .withoutResponse) var rawPacket = [UInt8]() if( self.connected && !self.wifiScanDone){ self.data.append(0x20) self.data.append(0x04) self.data.append(0x00) self.data.append(0x00) self.data.append(0x03) self.data.append(0x47) self.data.append(0x02) self.data.append(0x10) self.data.append(0x00) self.data.append(0xff) self.data.append(0xff) self.data.append(0xff) self.data.append(0xff) self.data.append(0xff) self.data.append(0xff) self.data.append(0xff) self.data.append(0xff) self.data.append(0xff) self.data.append(0xff) self.data.append(0x56) } else if (self.connected && self.wifiScanDone) { self.data.append(0x20) self.data.append(0x04) self.data.append(0x00) self.data.append(0x00) self.data.append(0x03) self.data.append(0x47) self.data.append(0x03) self.data.append(0x10) self.data.append(0x00) self.data.append(0xff) self.data.append(0xff) self.data.append(0xff) self.data.append(0xff) self.data.append(0xff) self.data.append(0xff) self.data.append(0xff) self.data.append(0xff) self.data.append(0xff) self.data.append(0xff) self.data.append(0x57) } print("writing data", String(describing: self.data)) let bytesToCopy: size_t = min(mtu, self.data.count) self.data.copyBytes(to: &rawPacket, count: bytesToCopy) var packetData = Data(bytes: &rawPacket, count: bytesToCopy) let stringFromData = String(data: packetData, encoding: .utf8) os_log("Writing %d bytes: %s", bytesToCopy, String(describing: stringFromData)) discoveredPeripheral.writeValue(packetData, for: transferCharacteristic, type: .withResponse) packetData.removeAll() self.data.removeAll() discoveredPeripheral.setNotifyValue(true, for: transferCharacteristic) self.writeIterationsComplete += 1 if writeIterationsComplete == defaultIterations { // Cancel our subscription to the characteristic } } override func prepare(for segue: UIStoryboardSegue, sender: Any?) { super.prepare(for: segue, sender: sender) let wifiSelectionController = segue.destination as? WifiSelectionTestViewController if segue.identifier == "skipSegue" { if EcojokoHelper.isEcojokoV2() { wifiSelectionController?.wifiNetworksFromBle = wifiNetworks } } } private func writeDataScanDone() { guard let discoveredPeripheral = discoveredPeripheral, let transferCharacteristic = transferCharacteristic else { return } // check to see if number of iterations completed and peripheral can accept more data let mtu = discoveredPeripheral.maximumWriteValueLength (for: .withResponse) var rawPacket = [UInt8]() self.data.append(0x20) self.data.append(0x04) self.data.append(0x00) self.data.append(0x00) self.data.append(0x03) self.data.append(0x47) self.data.append(0x03) self.data.append(0x10) self.data.append(0x00) self.data.append(0xff) self.data.append(0xff) self.data.append(0xff) self.data.append(0xff) self.data.append(0xff) self.data.append(0xff) self.data.append(0xff) self.data.append(0xff) self.data.append(0xff) self.data.append(0xff) self.data.append(0x57) let bytesToCopy: size_t = min(mtu, self.data.count) self.data.copyBytes(to: &rawPacket, count: bytesToCopy) var packetData = Data(bytes: &rawPacket, count: bytesToCopy) let stringFromData = String(data: packetData, encoding: .utf8) os_log("Writing scan mode %d bytes: %s", bytesToCopy, String(describing: stringFromData)) discoveredPeripheral.writeValue(packetData, for: transferCharacteristic, type: .withResponse) packetData.removeAll() self.data.removeAll() discoveredPeripheral.setNotifyValue(true, for: transferCharacteristic) self.writeIterationsComplete += 1 self.centralManager.cancelPeripheralConnection(discoveredPeripheral) self.cleanup() print("**** AT THIS POINT THE WIFI SCAN IS DONE ") self.scanWritingData = true if (self.connected && self.wifiScanDone && self.wifiNames.count == self.wifiCount && self.fillListDone) { if let centralManager = self.centralManager { centralManager.stopScan() // os_log("Scanning stopped") } self.data.removeAll(keepingCapacity: false) } } /* * If the connection fails for whatever reason, we need to deal with it. */ func centralManager(_ central: CBCentralManager, didFailToConnect peripheral: CBPeripheral, error: Error?) { os_log("Failed to connect to %@. %s", peripheral, String(describing: error)) cleanup() } /* * We've connected to the peripheral, now we need to discover the services and characteristics to find the 'transfer' characteristic. */ func centralManager(_ central: CBCentralManager, didConnect peripheral: CBPeripheral) { if( !wifiListing) { print("**** BEFORE CONNECTION ***** The available peripherals are : \(String(describing: peripheral.services))") os_log("Peripheral Connected") self.connected = true // Stop scanning self.centralManager.stopScan() os_log("Scanning stopped") connectionIterationsComplete += 1 writeIterationsComplete = 0 // Clear the data that we may already have // data.removeAll(keepingCapacity: false) // Make sure we get the discovery callbacks peripheral.delegate = self // Search only for services that match our UUID peripheral.discoverServices(nil) } }# Crashlytics - Stack trace# Platform: apple# Version: 1.1 (1.9)# Issue: 412239cf1ac3c946eb36a0f8fcd03787# Session: 411b37f768814760898b918fa9d8c1b3_DNE_0_v2# Date: Wed Apr 17 2024 08:14:28 GMT+0200 (heure d’été d’Europe centrale)com.apple.main-thread0 libsystem_kernel.dylib 0x1af8 mach_msg2_trap + 81 libsystem_kernel.dylib 0x1890 mach_msg2_internal + 802 libsystem_kernel.dylib 0x17a8 mach_msg_overwrite + 4363 libsystem_kernel.dylib 0x15e8 mach_msg + 244 CoreFoundation 0x3601c __CFRunLoopServiceMachPort + 1605 CoreFoundation 0x33f04 __CFRunLoopRun + 12086 CoreFoundation 0x33968 CFRunLoopRunSpecific + 6087 GraphicsServices 0x34e0 GSEventRunModal + 1648 UIKitCore 0x22aedc -[UIApplication _run] + 8889 UIKitCore 0x22a518 UIApplicationMain + 34010 Vattenfall 0xb4ec main + 20 (AppDelegate.swift:20)11 ??? 0x1b33d6d84 (Manquant)com.apple.uikit.eventfetch-thread0 libsystem_kernel.dylib 0x1af8 mach_msg2_trap + 81 libsystem_kernel.dylib 0x1890 mach_msg2_internal + 802 libsystem_kernel.dylib 0x17a8 mach_msg_overwrite + 4363 libsystem_kernel.dylib 0x15e8 mach_msg + 244 CoreFoundation 0x3601c __CFRunLoopServiceMachPort + 1605 CoreFoundation 0x33f04 __CFRunLoopRun + 12086 CoreFoundation 0x33968 CFRunLoopRunSpecific + 6087 Foundation 0x2b4a8 -[NSRunLoop(NSRunLoop) runMode:beforeDate:] + 2128 Foundation 0x554e8 -[NSRunLoop(NSRunLoop) runUntilDate:] + 649 UIKitCore 0x18dac8 -[UIEventFetcher threadMain] + 42010 Foundation 0x9ca9c __NSThread__start__ + 73211 libsystem_pthread.dylib 0x2a90 _pthread_start + 13612 libsystem_pthread.dylib 0x1fcc thread_start + 8com.google.firebase.crashlytics.MachExceptionServer0 FirebaseCrashlytics 0x1ef18 FIRCLSProcessRecordAllThreads + 1841 FirebaseCrashlytics 0x1f2f8 FIRCLSProcessRecordAllThreads + 11762 FirebaseCrashlytics 0x16598 FIRCLSHandler + 483 FirebaseCrashlytics 0x18d58 FIRCLSMachExceptionServer + 6884 libsystem_pthread.dylib 0x2a90 _pthread_start + 1365 libsystem_pthread.dylib 0x1fcc thread_start + 8com.apple.NSURLConnectionLoader0 libsystem_kernel.dylib 0x1af8 mach_msg2_trap + 81 libsystem_kernel.dylib 0x1890 mach_msg2_internal + 802 libsystem_kernel.dylib 0x17a8 mach_msg_overwrite + 4363 libsystem_kernel.dylib 0x15e8 mach_msg + 244 CoreFoundation 0x3601c __CFRunLoopServiceMachPort + 1605 CoreFoundation 0x33f04 __CFRunLoopRun + 12086 CoreFoundation 0x33968 CFRunLoopRunSpecific + 6087 CFNetwork 0x25ac48 estimatedPropertyListSize + 382288 Foundation 0x9ca9c __NSThread__start__ + 7329 libsystem_pthread.dylib 0x2a90 _pthread_start + 13610 libsystem_pthread.dylib 0x1fcc thread_start + 8Thread0 libsystem_kernel.dylib 0xa084 __workq_kernreturn + 81 libsystem_pthread.dylib 0x1f6c _pthread_wqthread + 3642 libsystem_pthread.dylib 0x1fc0 start_wqthread + 8Crashed: ZuluCalendar0 libswiftCore.dylib 0x4065e4 swift_isUniquelyReferenced_nonNull_native + 481 Foundation 0x2e75c specialized Set._Variant.insert(_:) + 2042 Foundation 0x2e8de4 _fromNSCalendarUnits(_:) + 1763 Foundation 0x2e410 _NSSwiftCalendar._components(_:from:) + 604 Foundation 0x2e274 @objc _NSSwiftCalendar._components(_:from:) + 805 CoreFoundation 0xc4e08 CFCalendarDecomposeAbsoluteTime + 3486 Security 0x11df64 __SecAbsoluteTimeGetGregorianDate_block_invoke + 647 libdispatch.dylib 0x3dd4 _dispatch_client_callout + 208 libdispatch.dylib 0x132c4 _dispatch_lane_barrier_sync_invoke_and_complete + 569 Security 0xaf0c SecCFCalendarDoWithZuluCalendar + 12810 Security 0x7ad4 der_encode_generalizedtime_body_repair + 23211 Security 0x76ac der_encode_plist_repair + 46812 Security 0x7560 der_encode_plist_repair + 13613 Security 0x7560 der_encode_plist_repair + 13614 Security 0x740c add_sequence_to_array + 13615 CoreFoundation 0x2507c -[__NSDictionaryM __apply:context:] + 12816 Security 0x13b80 der_encode_dictionary_repair + 12417 Security 0x740c add_sequence_to_array + 13618 CoreFoundation 0x2507c -[__NSDictionaryM __apply:context:] + 12819 Security 0x13b80 der_encode_dictionary_repair + 12420 Security 0x7560 der_encode_plist_repair + 13621 Security 0x740c add_sequence_to_array + 13622 CoreFoundation 0x2507c -[__NSDictionaryM __apply:context:] + 12823 Security 0x13b80 der_encode_dictionary_repair + 12424 Security 0xcc2c CFPropertyListCreateDERData + 10025 Security 0xcb78 SecTrustSerialize + 21626 CFNetwork 0x1ef68 _CFNetworkSetHSTSStoragePath + 9361227 CFNetwork 0xab3ac CFURLDownloadStart + 7476828 CFNetwork 0xaaedc CFURLDownloadStart + 7353629 CFNetwork 0xbc780 CFURLDownloadStart + 14538030 CFNetwork 0x1da190 CFHTTPCookieStorageUnscheduleFromRunLoop + 15891631 CFNetwork 0xbaa64 CFURLDownloadStart + 13792832 libboringssl.dylib 0x3b638 __boringssl_context_evaluate_trust_async_external_block_invoke + 44833 libdispatch.dylib 0x213c _dispatch_call_block_and_release + 3234 libdispatch.dylib 0x3dd4 _dispatch_client_callout + 2035 libdispatch.dylib 0xb400 _dispatch_lane_serial_drain + 74836 libdispatch.dylib 0xbf64 _dispatch_lane_invoke + 43237 libdispatch.dylib 0xd284 _dispatch_workloop_invoke + 175638 libdispatch.dylib 0x16cb4 _dispatch_root_queue_drain_deferred_wlh + 28839 libdispatch.dylib 0x16528 _dispatch_workloop_worker_thread + 40440 libsystem_pthread.dylib 0x1f20 _pthread_wqthread + 28841 libsystem_pthread.dylib 0x1fc0 start_wqthread + 8First, the code establishes a BLE connection to a specific peripheral, when he finds the right services and characteristics, it connects to them and asks the device to do a wifi scan. Then, the device searches for nearby wifi networks and sends the list to the app. The user selects one of the listed networks, fills the password and sends a connection request to the BLE peripheral.Here is the crash's stacktrace from Crashlytics. I'd like to get some help resolving the crash:Sample code of BLE Exchange source code: (can't provide full source code due to security and privacy compliance) :