title: utf8_(en|de)code removed from php7?
body: <p>I recently switched to PHP 7 on my development server, which has worked just fine - until now.</p>
  
  <p>Since I updated to <code>PHP 7.0.3-10+deb.sury.org~trusty+1</code> (earlier today), the <code>utf8_decode</code> and <code>utf8_encode</code> functions are no longer accessible. They were, however, in previous versions of PHP7. When called, a fatal error is raised.</p>
  
  <p>I read that these functions are provided by the <code>mbstring</code> extension, which I checked with <code>var_dump(extension_loaded('mbstring'));</code> is loaded.</p>
  
  <p>How can I get the above functions to work again?</p>