Hey Alex, I think what Jean is saying is that when you make a purchase and something is included in that purchase, then it should be included for at least the lifetime of your purchase. This is a basic principle of contracts.
After all, that is part of what you purchased even if it is "free." You made a purchase based upon the value of having this free item inclusive. In the case of an active subscription, that would be the life of the current subscription at minimum. So it seems to me that anyone that had an active subscription at the time that you made the choice to go to a paid model should at least have updates through the life of that particular subscription, if not for lifetime. For those who were involved in the evolution of the product such as beta testers there might be some additional benefits/incentives.
Let's be clear, I fully agree that your support is worthy of payment. However you offered a model that was an incentive to customers to purchase, so the right thing to do is to honor that at least through the term that customers did make a purchase. In retail, not doing so is known as a "bait-n-switch" tactic. I don't think that is what was intended, but it could easily appear that way to customers.