CDavExtranetAccounts::CatalogLastModifiedAt

protected function CatalogLastModifiedAt($collectionId, $filter = array())
{
	$order = array('TIMESTAMP_X' => 'DESC');
	$accounts = $this->LoadExtraAccounts($collectionId[0], 1, $order, $filter);
	if (!empty($accounts))
	{
		$lastModifiedExtranetAccount = reset($accounts);
		return $lastModifiedExtranetAccount['TIMESTAMP_X'];
	}

	return 0;
}