You should contact support@eventide.com with all your details to re-register the unit. You'll need to include the serial number, which is on a grey sticker on the side of the unit – send along a photo as people sometimes get these wrong.
But, while it is a good idea to re-register the unit, I'm not sure that you have to to get the upgrade, so if you can't be bothered, go to the update page and give it a try.
