title: Cannot assign an empty string to a string offset
body: <p>I've just installed PHP 7.1 and now I am seeing this error :</p>
  
  <pre><code>PHP Warning:  Cannot assign an empty string to a string offset in /postfixadmin/variables.inc.php on line 31
  </code></pre>
  
  <p>Line #31 :</p>
  
  <pre><code>$fDomains[0] = "";
  </code></pre>
  
  <p>How does on clear $fDomains[0] now in PHP 7.1?</p>