SMARTY: link rel seo

link-rel-seo.tpl

{* if per page is set add canonical link *}
{if isset($_REQUEST.items_per_page)}
	{assign var="page_current" value="/page-`$pagination.current_page`"}
	{assign var="can_url" value=$config.current_url|fn_query_remove:"items_per_page"|fn_url}
	{assign var="page_url" value=$can_url|replace:"$page_current":""}
	<link href="{$config.current_location}{$page_url}" rel="canonical">
{/if}

{* if paginated add rel prev/next links *}
{if $pagination.current_page >= 1}
	{assign var="can_url" value=$config.current_url|fn_query_remove:"items_per_page"|fn_url}

	{assign var="page_prev" value="page-`$pagination.prev_page`"}
	{assign var="page_next" value="page-`$pagination.next_page`"}
	{assign var="page_current" value="page-`$pagination.current_page`"}

	{assign var="page_prev_url" value=$can_url|replace:"$page_current":"$page_prev"}
	{assign var="page_next_url" value=$can_url|replace:"$page_current":"$page_next"}

	{if $pagination.prev_page !== "0"}
		<link href="{$config.current_location}{$page_prev_url}" rel="prev">
	{/if}
	{if $pagination.next_page == "2"}
		<link href="{$config.current_location}{$can_url}page-{$pagination.next_page}/" rel="next">
	{elseif $pagination.next_page > "2"}
		<link href="{$config.current_location}{$page_next_url}" rel="next">
	{/if}
{/if}

Hello,

I try add this code in my header.tpl file to print these link tags. After this my site return me this error:

Fatal error: Smarty error: [in header.tpl line 36]: [plugin] modifier 'fn_query_remove' is not implemented (core.load_plugins.php, line 118) in Smarty.class.php on line 1095

This error I receive and for fn_url. I use Smarty version 2.6.18. How I can remove this error?

Thank you in advance!