get_site_version

[nomik05]

Hi all! I have a little problem here with this function

Code:

<link href="<?php get_theme_url(); ?>/style.css?v=<?php echo get_site_version(); ?>" rel="stylesheet">

This returns
Fatal error: Call to undefined function get_site_version() in /var/www/vhosts/mysite.gr/httpdocs/theme/Innovation/header.inc.php on line 24

And what is the point to pass arguments to css file???