iOS 7 Only App Crashes at Startup

You probably did what I did, and overzealously cut and replaced the compiler warnings for UITextAttributeTextShadowColor and UITextAttributeTextShadowOffset. So you had code that looked like this:

NSDictionary *titleAttributes = @{UITextAttributeTextColor: [UIColor whiteColor],
                                  UITextAttributeTextShadowColor: [UIColor blackColor],
                                  UITextAttributeTextShadowOffset: [NSValue valueWithUIOffset:UIOffsetMake(1, 0)],
                                  UITextAttributeFont: [UIFont titleBolder]};
[[UINavigationBar appearance] setTitleTextAttributes:titleAttributes];

and replaced them both with NSShadowAttributeName, and ended up with some code like this:

NSDictionary *titleAttributes = @{NSForegroundColorAttributeName: [UIColor whiteColor],
                                  NSShadowAttributeName: [UIColor blackColor],
                                  NSShadowAttributeName: [NSValue valueWithUIOffset:UIOffsetMake(1, 0)],
                                  NSFontAttributeName: [UIFont titleBolder]};
[[UINavigationBar appearance] setTitleTextAttributes:titleAttributes];

What you need to do is have one attribute NSShadowAttributeName, and create an instance of NSShadow that contains the shadow color and shadow offset.

NSShadow *shadow = [[NSShadow alloc] init];
shadow.shadowColor = [UIColor blackColor];
shadow.shadowOffset = CGSizeMake(1, 0);
NSDictionary *titleAttributes = @{NSForegroundColorAttributeName: [UIColor whiteColor],
                                  NSShadowAttributeName: shadow,
                                  NSFontAttributeName: [UIFont titleBolder]};
[[UINavigationBar appearance] setTitleTextAttributes:titleAttributes];