There is no news.php file in X-Cart 5. The code was for X-Cart 4 and it will not work in X-Cart 5, unfortunately.
When working with e-mail newsletters, there is a high risk if getting your server added to a black list. If this happens, none of your customers will likely receive an e-mail from you.
That's why in X-Cart 5 we removed the built-in newsletter logic and created a
module that integrates with MailChimp who are experts in working with e-mail newsletters. However, the module does not have the function to display the subscription form in the footer, so you still require someone to customize it for you by creating a small custom module.