DateTime::diff() náhrada

$d_start = new DateTime(date('Y-m-d H:i:s',strtotime($r['start'])));
                    $d_end  = new DateTime(date('Y-m-d H:i:s',mktime(0,0,0,$month,date("t",mktime(0,0,0,$month,1,$year)),$year)));
                    $diff = $d_start->diff($d_end);