I think the policy is fine. Paying for updates after a certain amount of time is not just fair, it's likely critical to maintaining a viable business model. What would be helpful to the user (and the may already be in place -- we just upgraded to the latest) is for the popup to have an additional option. Either
- Dismiss
- Update to most recent included update (if there is one) or
- Update to most recent product.
It would also be a little less in your face if it only appeared every four or five startups instead of every time it starts.