How to upgrade to the latest version
You can download the original version you purchased and any free upgrades in the My Downloads & Licenses section of your user account.
If the latest version is not available it means that it is not a free upgrade and you will need to purchase the latest version.
"Name Your Own Price" items usually will require you to buy them again as the policy asks that you name the price of the upgrade. You can of course edit the upgrade price to whatever you feel the upgrade is worth to you.