Get the installed version of Drupal

drupal_current.php

<?php
/**
 * Get Drupal 7 current version
 */

$version = NULL;
$version_file = 'includes/bootstrap.inc';

// Path to installation
$install_path = '/home/user/website.com/public_html';


$file = realpath($install_path . '/' . $version_file);
include_once $file;

$version = defined('VERSION') ? VERSION : FALSE;

echo $version;
//return VERSION;