title: How do I ignore UILocalNotification on devices with OS's older than iOS4?
body: <p>I am using local notifications in a app I'm making.</p>
  
  <p>I use this: </p>
  
  <pre><code>Class myClass = NSClassFromString(@"UILocalNotification");
  if (myClass) {
  //Local Notification code
  }
  </code></pre>
  
  <p>To avoid using UILocalNotifications when not supported.</p>
  
  <p>But my app crashes on launch with this error code:</p>
  
  <blockquote>
    <p>warning: Unable to read symbols for
    "/Library/MobileSubstrate/MobileSubstrate.dylib"
    (file not found). dyld: Symbol not
    found:
    _OBJC_CLASS_$_UILocalNotification   Referenced from:
    /var/mobile/Applications/FCFFFCB2-A60B-4A8D-B19B-C3F5DE93DAD2/MyApp.app/MyApp
    Expected in:
    /System/Library/Frameworks/UIKit.framework/UIKit</p>
    
    <p>Data Formatters temporarily
    unavailable, will re-try after a
    'continue'. (Not safe to call dlopen
    at this time.)
    mi_cmd_stack_list_frames: Not enough
    frames in stack.
    mi_cmd_stack_list_frames: Not enough
    frames in stack.</p>
  </blockquote>
  
  <p>How can i prevent this?</p>