=======================================================
    function getOverview($first,$last) {
        $format = $this->getOverviewFmt();

        $this->command("XOVER $first-$last");
        foreach($this->_getData() as $line) {
            $i=0;
            foreach(explode("\t",$line) as $line) {
                $message[$format[$i++]] = $line;
            }
            $messages[$message["Message-ID"]] = $message;
        }

-        $this->command("XROVER $first-$last");
-        foreach($this->_getData() as $line) {
-            $i=0;
-            foreach(explode("\t",$line) as $line) {
-                $message[$format[$i++]] = $line;
-           }
-            $messages[$message["Message-ID"]] = $message;
-        }
        return $messages;
    }
===========================================================

XROVER? It's an error function for NNTP service.