Wordpress - Where does WordPress store version number?

If you need to get the wordpress version in your script, there is a global variable:

$wp_version (right now it's something like '3.1-RC3-17376')

It contains the wordpress version.

If you need to acquire if from a file, you can read it from /wp-includes/version.php:

function getWPVersion() {
    $path = '/path/to/wp-install';
    include $path.'/wp-includes/version.php';
    return $wp_version;
}

Wordpress Version Variables

There is more information available in that file:

• $wp_version - The WordPress version string ('3.1-RC3-17376')
• $wp_db_version - Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema (17056)
• $tinymce_version - The TinyMCE version string ('3393')
• $manifest_version - Holds the cache manifest version ('20111113')
• $required_php_version - Holds the required PHP version ('4.3')
• $required_mysql_version - Holds the required MySQL version ('4.1.2')

The codex says its in wp-includes/version.php.

add_action( 'after_setup_theme', 'getWPVersion' );

function getWPVersion() {

    echo $GLOBALS['wp_version'];

}