Airplane_Mode_Core::ms_admin_menu_items PHP Method

        public function ms_admin_menu_items()
        {
            // Bail if disabled or not on our network admin.
            if (!$this->enabled() || !is_network_admin()) {
                return;
            }
            // Remove the items.
            remove_submenu_page('index.php', 'upgrade.php');
        }