Now supporting Zen Cart 1.5.8a and above (including 2.0.x). Validated on PHP versions 7.4 through 8.3.
For additional questions and documentation, please see the plugin's readme.html.
Zen Cart Plugin Download: https://www.zen-cart.com/downloads.php?do=file&id=2164
Zen Cart Support Thread: https://www.zen-cart.com/showthread.php?223003-VAT4EU-Support-Thread