Prestashop order-confirmation.php page error

Estimated duration: not set
Description: Hello,

We have a error on the /order-confirmation.php of prestashop 1.5.4.

When a customer makes payment via sagepay they are just presented with a blank page, with error reporting switched on the following error is displayed:


Warning: File /home/*******/public_html/*************co.uk/order-confirmation.php is deprecated
in /home/*******/public_html/*************.co.uk/classes/Tools.php on line 1845


I would like the error fixing, so please quote accordingly.

Regards
Paul