Ok please bear with me I am new to this topic.

I wish to upgrade HESK on our server. Currently we are running v2.2.
The documentation suggests that HESK now only runs on PHP5. I mentioned this to our provider, HostGator, and they informed me:
"Unfortunately, it appears this account is on a shared server.
Php 5 cannot be installed on this server, they would need to upgrade to a VPS or Dedicated."
So, my question for you guys then is what versions of PHP does v2.2 of HESK support? I assume we must currently be on PHP 4 or earlier in order to be using HESK v2.2? I didn't actually ask what version of PHP we are on currently and am not sure how to check.

Any help appreciated.
Jake