If I sell you code that is compatible with the current version of UNA, I don't see why I should be obligated to provide a free update for a new version tomorrow. If I choose to sell an update, I will; if not, I won’t. If you agree to these terms, you are welcome to purchase it; if not, you are not obligated to. I provide you with open-source code today, and if you need an update in the future, you are free to hire someone else to make the necessary changes. Unless there is a contractual agreement to provide updates, you cannot demand them for free. As an example, all the products I've seen from UNA INC with updates typically require an annual subscription. If you don’t buy a subscription, you can’t expect to receive updates. If you receive a free update, that doesn't mean it's mandatory, it's just voluntary.

All software products sold with a subscription for updates are eligible to receive updates anywhere on the internet. If you do not purchase a subscription for updates, I see no reason why you should receive them. Therefore, a product sold without updates will, by definition, only receive voluntary updates. However I believe that any software developer should be honest and clearly outline in the sales contract whether the product will receive future updates, ensuring transparency and avoiding any confusion. Otherwise, some customers might consider it a scam.