Sorry to post a woolly question but here goes.

I am in the final stages of my 1.5 upgrade and can't get this payment module to work. I have no other issues.

I have old and new shops (tienda_139 and tienda_15) on the same local server

When I confirm the order and I get transferred to the gateway, I get the payment page displayed correctly with the 139 shop and an error with the 1.5 shop.
The 4b gateway is archaic rubbish, I can't get any error messages from it.
The payment module code is the same in both shops, I have tried the order.php from 139 and the database details are identical for this module.

I just wanted to know if there is anything new in the 1.5 code relating to payment modules that may impinge on old code.
thanks
Steve