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.