public function settingsUpdate($keyvals)
    {
        $allSettings = $this->settingsGetAll();
        $different = false;
        foreach ( $keyvals as $k => $v ) {
            if ( array_key_exists ($k, $allSettings ) ) {
                if ( $v != $allSettings[$k] ) {
                    $different = true;
                    break;
                }
            } else {
                $different = true;
                break;
            }
        }
        if ( ! $different ) return;
        $newSettings = array_merge($allSettings, $keyvals);
        return $this->settingsSetAll($newSettings);
    }