Most probably you've been using a version released during the "active" subscription plan period. Our licenses are perpetual - any of your licenses will never expire and you can continue using our products forever. In addition with the purchase of our plug-ins, we provide automatically one-year / three-years maintenance plan. Once the subscription plan expires, you are not able to use releases published after the subscription end date, but you still can use versions released before that date.
Don't feel obliged to update immediately your maintenance plan expire - if you'll be not using any new features and improvements there is no need to renew the subscription plan, as your "actual" version will remain working. Only if wanted, you can renew your subscription (at any time) and get access to latest upgrades.
Hope that clears it up.