The latest version of the Master Genealogist is 7.04. If you download the trial version, you will get that version. If you decide to purchase it, that will be the version you unlock.
If you go to http://www.whollygenes.com/Merchant2/merchant.mvc?Screen=UPGRADES
You will see that currently 7.04 is the latest available version.
I am not affiliated with whollygenes in anyway, just a happy user, but thought you'd like to know what the latest version was and how to find it in the future on their website.