Fatal error: Uncaught Error: Call to undefined function is_main_site() in /data05/virt11394/domeenid/www.tyrs.ee/htdocs/seminar/wp-includes/update.php:431 Stack trace: #0 {main} thrown in /data05/virt11394/domeenid/www.tyrs.ee/htdocs/seminar/wp-includes/update.php on line 431