Reverting back to an earlier version of Pro Tools

I am an admitted novice with Pro Tools. I have an iMac Intel i3, 2GHz system that I want to upgrade to PT 10 from PT 8LE. Researching the compatibility issues I have found that my system would require Mac OS 10.7.4 and Pro Tools 10.3.1.

My question is, if I purchase Pro Tools outright and the version is above my threshold of 10.3.1, is there a way to revert to a lower version of Pro Tools with the new activation code?



Any and all help would be appreciated.



Gary