/**
  * Tells if we are still in the old preferences system
  *
  * @param bool $core_upgrade True if core upgrading (after initial install)
  *
  * @return bool
  */
 static function isOldPrefSystem($core_upgrade = false)
 {
     if (self::$_old_pref_system === null || $core_upgrade) {
         $ds = CSQLDataSource::get("std");
         self::$_old_pref_system = $ds->loadField("user_preferences", "pref_name") != null;
     }
     return self::$_old_pref_system;
 }