title: Deprecated constant in iOS
body: <p>I building an app targeting iOS 3.1.3 and later and I've run into a problem with <code>UIKeyboardBoundsUserInfoKey</code>. Turns out it is deprecated in iOS 3.2 and later. What I did was use the following code to use the right key depending on the iOS version:</p>
  
  <pre><code>if ([[[UIDevice currentDevice] systemVersion] compare:@"3.2" options:NSNumericSearch] != NSOrderedAscending)
      [[aNotification.userInfo valueForKey:UIKeyboardFrameEndUserInfoKey] getValue: &amp;keyboardBounds];
  else [[aNotification.userInfo valueForKey:UIKeyboardBoundsUserInfoKey] getValue: &amp;keyboardBounds];
  </code></pre>
  
  <p>And this actually works fine, but Xcode warns me that <code>UIKeyboardBoundsUserInfoKey</code> is deprecated. How can I get rid of this warning without having to suppressing any other warnings?</p>
  
  <p>Also, is there a way to simply check if <code>UIKeyboardBoundsUserInfoKey</code> is defined to avoid having to check the iOS version? I tried checking if it was <code>NULL</code> or <code>nil</code> and even weaklinking UIKit but nothing seemd to work.</p>
  
  <p>Thanks in advance</p>