Fatal error: Uncaught Error: Call to undefined function is_main_site() in /var/www/u0274343/data/www/reasunmed.ru/mama/wp-includes/update.php:711
Stack trace:
#0 {main}
thrown in /var/www/u0274343/data/www/reasunmed.ru/mama/wp-includes/update.php on line 711