While you’re a subscriber, you’ll receive regular Substrate software updates (currently monthly), both source and binary. The authors will be available for personalized support and architectural review.
Should you ever decide to cancel your subscription, you’ll retain your license to the last version of Substrate released prior to cancellation, forever. You’ll be free to continue using it within your company. You’ll be free to modify its source code as you see fit for use within your company, though you won’t have support from the authors. You will not have the right to open-source Substrate yourself.