<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
{/if}
- <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="{$lang}" lang="{$lang}">
+ <html{if $is_xhtml} xmlns="http://www.w3.org/1999/xhtml" xml:lang="{$lang}" lang="{$lang}"{/if}>
<head>
<title>{$head_title|@default:$blogTitle}{if $head_subtitle} - {$head_subtitle}{/if}</title>
{serendipity_hookPlugin hook="frontend_header"}