Firebase initWithUrl在iOS 5.1上崩溃

我正在开发一个Firebase应用程序，用于我的旧iPad第一代（iOS 5.1.1）。它在模拟器和其他设备上运行良好，但当我将其加载到iPad上进行测试时，我会收到如下崩溃：

#0  0x33860f86 in objc_msgSend ()
#1  0x33862f94 in objc_retain ()
#2  0x000d26a0 in -[FRepoManager setQueue:] at /Users/mtse/Dev/firebase/firebase-client-objc/Firebase/Firebase/Core/FRepoManager.m:24
#3  0x33fdc5aa in dispatch_once_f$VARIANT$up ()
#4  0x000d1a80 in _dispatch_once [inlined] at /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS8.1.sdk/usr/include/dispatch/once.h:68
#5  0x000d1a70 in +[FRepoManager singleton] at /Users/mtse/Dev/firebase/firebase-client-objc/Firebase/Firebase/Core/FRepoManager.m:37
#6  0x000e6736 in -[Firebase initWithUrl:] at /Users/mtse/Dev/firebase/firebase-client-objc/Firebase/Firebase/Firebase.m:54
#7  0x000c6f82 in -[AppDelegate application:didFinishLaunchingWithOptions:] at /xxx/AppDelegate.m:25
#8  0x3337acaa in -[UIApplication _callInitializationDelegatesForURL:payload:suspended:] ()
#9  0x333747dc in -[UIApplication _runWithURL:payload:launchOrientation:statusBarStyle:statusBarHidden:] ()
#10 0x33342ac2 in -[UIApplication handleEvent:withNewEvent:] ()
#11 0x33342566 in -[UIApplication sendEvent:] ()
#12 0x33341f3a in _UIApplicationHandleEvent ()
#13 0x3393422a in PurpleEventCallback ()
#14 0x35c16522 in __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE1_PERFORM_FUNCTION__ ()
#15 0x35c164c4 in __CFRunLoopDoSource1 ()
#16 0x35c15312 in __CFRunLoopRun ()
#17 0x35b984a4 in CFRunLoopRunSpecific ()
#18 0x35b9836c in CFRunLoopRunInMode ()
#19 0x3337386a in -[UIApplication _run] ()
#20 0x33370cd4 in UIApplicationMain ()
#21 0x000c778c in main at /xxx/main.m:14

当代码到达这一行时，就会发生这种情况：

    Firebase *ref = [[Firebase alloc] initWithUrl:kFirebaseURL];

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我甚至尝试将Firebase框架降级为较旧的框架，但问题仍然存在。我也设置了-ObjC链接器标志。有没有办法解决这个问题？

抱歉，Firebase SDK不再支持iOS 5.x。您可以尝试使用SDK，看看它是否能正常工作，但我不知道。

您可以通过将框架降级到（直接链接到ZIP文件）来解决此问题-这是最新版本，在配备iOS 5.1.1的iPad 1上不会发生此崩溃