Maintenance mode

This snippet will show a maintenance message for all users except administrators. This can be left on the WordPress site, and enabled as needed.

<?php
2
3add_action('get_header', function() {
4 
5    if(!current_user_can('manage_options')){
6    
7        wp_die('The site is in maintenance mode, please check back later.', 
8        'The site is in maintenance mode, please check back later.', array('response' => '503'));
9    }
10});