WP 4.4 – Fail to upgrade

Fatal error: Cannot redeclare get_network_option() (previously declared in /home/webv/public_html/wp-includes/option.php:1073) in /…/../public_html/wp-content/plugins/wp-multi-network/includes/functions-wp-ms-networks.php on line 746

https://wordpress.org/plugins/wp-multi-network/