Ok, so to resume to confirm I understand all of this. We currently need to go to PHP 7 on the server as requested by our Web Hosting provider. So to do this, we need latest version of Zen Cart, i.e. v1.5.6c.
We are currently licenced for Atrex 15, which is supported by the eCommerce/Zen Cart Utility v 22.214.171.124.
eCommerce/Zen Cart Utility v 126.96.36.199 is not compatible with Zen Cart v1.5.6c and there is absolutely no way to make it work together?
If not, we therefore need eCommerce/Zen Cart Utility v 7, which in turn does not work with Atrex 15, which means that we need to upgrade to a higher version of Atrex?
Thanks for providing this information.