You cannot. Xampp comes as distribution with many "hardcoded" dependencies.
If you like to use your own releases of Apache, PHP, MySQL etc., simply dont use Xampp, but install all components separately. This is not as difficult as it might appear, each component is coming with a full featured installer and it is well documented, how to connect Apache to PHP and MySQL etc.
But it is definately quite impossible to "break out" from a Xampp Installation.