Ich habe die Meldung erhalten:

Fatal error: Cannot pass parameter 2 by reference in [...]common.inc.php on line 69.

Die line 69 lautet:

serendipity_common_adduser::sendMail($author['username'], (function_exists('serendipity_specialchars') ? serendipity_specialchars($string) : htmlspecialchars ...