This document has details and links back to Pro Tools 7. If you click on one of the entries, in this case below, my Pro Tools HD 7. My list actually goes all the way back to a Pro Tools 6LE to 7. You will then see a list and you will see a list of your products, that will look a bit like this depending on what products you have. Your first port of call should be your Avid Master Account.
These two documents are the master documents that provide links back to documents covering the current System Requirements as well as the System Requirements for older versions of Pro Tools. As a rule, they have undertaken comprehensive testing to draw up these compatibility documents.
