XenForo version 1.0 and 1.1 both have basically the same requirements for your hosting account setup. A modern operating system with a web server that's up to date that supports the PHP5 programming language and the MySQL5 database server.
The official XenForo requirements script can be found here: Download the XenForo test script
What it can't do is test the MySQL Server version via PHP, additional steps are required. This script helps you with that final test-step.
Via phpinfo(); you can find the MySQL API version, but it's not exactly the server's version number per-se. In order to find it, you will have to edit the .php file with a text editor, enter your credentials at the top, before you can run it from the browser.
It will report back if your user/pass to the database is invalid, if the database you're planning to use for xenforo is invalid, and if it couldn't establish a connection to the MySQL database or not because of this.
When successful, it will spit out the version number. Which should be higher than 5.0
You do not need the xenforo test script, and you can delete the .php file from your server after testing.
Download: (I recommend right click on the mouse, and save the file to your hard drive)