Here is what an administrator of the FB Oura Science just posted:
"Okay guys- I contacted someone at Oura and got a response regarding the subscription for current users :
“If you’re currently a Gen2 Oura Ring Member and decide to stick with your Gen2 ring without upgrading to the new Oura Ring Generation 3, we’ll continue to support your product with routine software and firmware updates for up to 2 years post Gen3 release. You’ll still have access to all the same features currently available on your Gen2 ring. However, because there are technological differences between Gen2 and Gen3, as we continue to release new features, many of them may not be available on Gen2 due to limitations in its interior hardware.”