Here's the scoop on upgrading from their website
Because of our Lifetime License, if you've purchased a previous version of Axialis IconWorkshop™, you're entitled for a free upgrade to the latest version.
However, this version requires a Product Key to be activated. This key is very important because it will permit you to access numerous services from Axialis in the future (including the lifetime online upgrades). If you're a previous version owner (prior to 5.0 - name was "AX-Icons") you did not receive your personal product key with your purchase. Therefore, the online upgrade using the built-in feature is not possible.
All registered customers have received a download link to get the full version a few days after the official release.
If you're already a customer and did not receive the upgrade link, please contact us providing your personal data (order# beginning with RE, name, company, purchase date...). We'll send you your link and your product key.
The part in Bold was added by me.