$upgrade = new CRM_Upgrade_Form();
$upgrade->setVersion($rev);
CRM_Utils_System::flushCache();
$config = CRM_Core_Config::singleton();
$config->userSystem->flush();
$upgrade = new CRM_Upgrade_Form();
$upgrade->setVersion($rev);
CRM_Utils_System::flushCache();
$config = CRM_Core_Config::singleton();
$config->userSystem->flush();