title: Why is mb_convert_case in PHP 5.4 breaking my string, when in 5.2 it doesn't?
body: <p>I have the following code:</p>
  
  <pre><code>header('Content-type: text/html; charset=utf-8');
  $str = 'áá áá';
  echo $str."\n";
  echo mb_convert_case($str, MB_CASE_TITLE)."\n";
  echo bin2hex($str)."\n";
  echo bin2hex(mb_convert_case($str, MB_CASE_TITLE))."\n";
  </code></pre>
  
  <p>Using PHP 5.2.2, I get the following output:</p>
  
  <pre><code>áá áá
  áá áá
  c3a1c3a120c3a1c3a1
  c3a1c3a120c3a1c3a1
  </code></pre>
  
  <p>Using PHP 5.4.3, I get this:</p>
  
  <pre><code>áá áá
  á� á�
  c3a1c3a120c3a1c3a1
  c3a1e3a120c3a1e3a1
  </code></pre>
  
  <p>My expected output in both cases would have been:</p>
  
  <pre><code>áá áá
  Áá Áá
  c3a1c3a120c3a1c3a1
  c381c3a120c381c3a1
  </code></pre>
  
  <p>So I have two questions:</p>
  
  <ol>
  <li>Why isn't the á being converted to Á?</li>
  <li>Why is PHP 5.4 breaking my strings?</li>
  </ol>