Here is a crash report for the release version (exact same build as the TestFlight beta, which doesn't crash). The release version crashes immediately when the app is run. I don't think it loads any of my code at all.
This crash is reproducible. If you use an iOS 10 device to run the release version of my app (details in bug report FB7692530), it will crash. If you run the TestFlight beta, it will not crash.
Crash report follows:
Incident Identifier: 28D0FA6B-4AB1-4C37-A0A7-EF284E419E4C
CrashReporter Key: 3fcddbe8a8f49dd3eca438c0983d3a49990d48e5
Hardware Model: iPhone5,2
Process: <appname> [328]
Path: /private/var/containers/Bundle/Application/55AC7D1A-83D5-44B7-B55D-F1061318BBA3/<appname>.app/<appname>
Identifier: com.<company>.<appname>
Version: <version> (<build>)
Code Type: ARM (Native)
Role: Foreground
Parent Process: launchd [1]
Coalition: com.<company>.<appname> [402]
Date/Time: 2020-05-07 13:32:39.7419 +0100
Launch Time: 2020-05-07 13:32:37.0000 +0100
OS Version: iPhone OS 10.3.4 (14G61)
Report Version: 104
Exception Type: EXC_BAD_ACCESS (SIGSEGV)
Exception Subtype: KERN_INVALID_ADDRESS at 0x0a8a00d4
Termination Signal: Segmentation fault: 11
Termination Reason: Namespace SIGNAL, Code 0xb
Terminating Process: exc handler [0]
Triggered by Thread: 0
Thread 0 name:
Thread 0 Crashed:
0 ??? 0x0a8a00d4 0 + 176816340
Thread 1:
0 libsystem_pthread.dylib 0x1af9a454 start_wqthread + 0
Thread 2:
0 libsystem_kernel.dylib 0x1aee673c __workq_kernreturn + 8
1 libsystem_pthread.dylib 0x1af9a8ea _pthread_wqthread + 1150 (pthread.c:2205)
2 libsystem_pthread.dylib 0x1af9a45c start_wqthread + 8
Thread 3:
0 libsystem_kernel.dylib 0x1aee673c __workq_kernreturn + 8
1 libsystem_pthread.dylib 0x1af9a8ea _pthread_wqthread + 1150 (pthread.c:2205)
2 libsystem_pthread.dylib 0x1af9a45c start_wqthread + 8
Thread 4:
0 libsystem_kernel.dylib 0x1aee673c __workq_kernreturn + 8
1 libsystem_pthread.dylib 0x1af9a8ea _pthread_wqthread + 1150 (pthread.c:2205)
2 libsystem_pthread.dylib 0x1af9a45c start_wqthread + 8
Thread 5 name:
Thread 5:
0 libsystem_kernel.dylib 0x1aed0900 mach_msg_trap + 20
1 libsystem_kernel.dylib 0x1aed06e0 mach_msg + 44 (mach_msg.c:103)
2 CoreFoundation 0x1b6d3be2 __CFRunLoopServiceMachPort + 144 (CFRunLoop.c:2527)
3 CoreFoundation 0x1b6d2064 __CFRunLoopRun + 1436 (CFRunLoop.c:2870)
4 CoreFoundation 0x1b6251ae CFRunLoopRunSpecific + 470 (CFRunLoop.c:3113)
5 CoreFoundation 0x1b624fd0 CFRunLoopRunInMode + 104 (CFRunLoop.c:3143)
6 Foundation 0x1bf79af4 -[NSRunLoop(NSRunLoop) runMode:beforeDate:] + 258 (NSRunLoop.m:367)
7 Foundation 0x1bf9676c -[NSRunLoop(NSRunLoop) runUntilDate:] + 86 (NSRunLoop.m:411)
8 UIKit 0x212aead8 -[UIEventFetcher threadMain] + 128 (UIEventFetcher.m:313)
9 Foundation 0x1c05d8ea __NSThread__start__ + 1122 (NSThread.m:1163)
10 libsystem_pthread.dylib 0x1af9c93a _pthread_body + 216 (pthread.c:697)
11 libsystem_pthread.dylib 0x1af9c85c _pthread_start + 234 (pthread.c:744)
12 libsystem_pthread.dylib 0x1af9a468 thread_start + 8
Thread 6:
0 libsystem_pthread.dylib 0x1af9a454 start_wqthread + 0
Thread 7 name:
Thread 7:
0 libsystem_kernel.dylib 0x1aed0900 mach_msg_trap + 20
1 libsystem_kernel.dylib 0x1aed06e0 mach_msg + 44 (mach_msg.c:103)
2 CoreFoundation 0x1b6d3be2 __CFRunLoopServiceMachPort + 144 (CFRunLoop.c:2527)
3 CoreFoundation 0x1b6d2064 __CFRunLoopRun + 1436 (CFRunLoop.c:2870)
4 CoreFoundation 0x1b6251ae CFRunLoopRunSpecific + 470 (CFRunLoop.c:3113)
5 CoreFoundation 0x1b624fd0 CFRunLoopRunInMode + 104 (CFRunLoop.c:3143)
6 AVFAudio 0x3223682e GenericRunLoopThread::Entry(void*) + 142 (GenericRunLoopThread.h:106)
7 AVFAudio 0x3225f58e CAPThread::Entry(CAPThread*) + 154
8 libsystem_pthread.dylib 0x1af9c93a _pthread_body + 216 (pthread.c:697)
9 libsystem_pthread.dylib 0x1af9c85c _pthread_start + 234 (pthread.c:744)
10 libsystem_pthread.dylib 0x1af9a468 thread_start + 8
Thread 8 name:
Thread 8:
0 libsystem_kernel.dylib 0x1aed0900 mach_msg_trap + 20
1 libsystem_kernel.dylib 0x1aed06e0 mach_msg + 44 (mach_msg.c:103)
2 CoreFoundation 0x1b6d3be2 __CFRunLoopServiceMachPort + 144 (CFRunLoop.c:2527)
3 CoreFoundation 0x1b6d2064 __CFRunLoopRun + 1436 (CFRunLoop.c:2870)
4 CoreFoundation 0x1b6251ae CFRunLoopRunSpecific + 470 (CFRunLoop.c:3113)
5 CoreFoundation 0x1b624fd0 CFRunLoopRunInMode + 104 (CFRunLoop.c:3143)
6 AudioToolbox 0x1e2441b6 GenericRunLoopThread::Entry(void*) + 142 (GenericRunLoopThread.h:106)
7 AudioToolbox 0x1e425fce CAPThread::Entry(CAPThread*) + 154
8 libsystem_pthread.dylib 0x1af9c93a _pthread_body + 216 (pthread.c:697)
9 libsystem_pthread.dylib 0x1af9c85c _pthread_start + 234 (pthread.c:744)
10 libsystem_pthread.dylib 0x1af9a468 thread_start + 8
Thread 9:
0 libsystem_pthread.dylib 0x1af9a454 start_wqthread + 0
Thread 10:
0 libsystem_pthread.dylib 0x1af9a454 start_wqthread + 0
Thread 0 crashed with ARM Thread State (32-bit):
r0: 0xffffffff r1: 0x0a8a00d5 r2: 0x00000030 r3: 0x00000078
r4: 0x43870000 r5: 0x00000000 r6: 0x00000000 r7: 0x00000000
r8: 0x00000000 r9: 0x0037b838 r10: 0x0037ba08 r11: 0x165b9b50
ip: 0x0037b92c sp: 0x0037b850 lr: 0x001238f1 pc: 0x0a8a00d4
cpsr: 0x60000030
[binary images cut] - If you need this, please let me know.