Back button is not visible in iOS 7

Question

I have some weird trouble about iOS 7. I have an UINavigationBar in my app and it works perfect for iOS 6;

-- IOS 6 --

Answer 1

By the way, if you have to keep support ios 6 version like me, use that;

   if (floor(NSFoundationVersionNumber) <= NSFoundationVersionNumber_iOS_6_1)
        {
            // My iOS 6 back button background 
            self.navigationController.navigationBar.tintColor = [UIColor colorWithRed:39.0f/255.0f green:184.0f/255.0f blue:199.0f/255.0f alpha:1.0];
        }
        else
        {
            self.navigationController.navigationBar.tintColor = [UIColor whiteColor];
        }