The Plesk firewall is a tool you can use to improve the security of your Plesk for Linux server by restricting network connections to and/or from the server.
@Dork, thank you, but I meant a screenshot of your system. We just don't know what you see. This is also what I meant by my initial "what's displayed instead" question and Kaspar's "can you post a screenshot".
I followed the Plesk docu and runed into trouble.
So I think it's not a good idea to change the version of a software and not to change the related part of the documentation