I don't think this is possible from inside Website X5.

But you could open your public_html folder and disable the server’s signature used to identify the server, by using the following code in your .htaccess file:

# Disable server signature

ServerSignature Off

You will not be able to turn that off on a shared server account. You would need to be on a dedicated or VPS server account with root access in order to make changes of that nature.