<?php
/*
 * @wordpress-plugin
 * Plugin Name:       wp_maintenance_mode
 * Plugin URI:        http://pepestarboy.com
 * Description:       Switch to maintenance mode.
 * Version:           1.0.0
 * Author:            Sair
 * Author URI:        http://pepestarboy.com
 */


function wp_maintenance_mode_plugin_156812() {
 if (!current_user_can('edit_themes') || !is_user_logged_in()) 
 { 
    wp_die('<h1>MAINTENANCE</h1><br/>OPEN SOON!', 'MAINTENANCE');
  }
}
add_action('get_header', 'wp_maintenance_mode_plugin_156812');