@burnbum55, fundamentally, the stable subscription is per appliance, and of course is very much appreciated by the team to fund the resources needed to do development, testing, storage, this forum, what have you. At this time, the existing subscription revenue does not cover those expenses, which is also one of the reasons for the partnership with the OpenCollective (see link above), but still that does not cover everything either.
Of course, I would be remiss if I didn’t mention, that you can also run Rockstor using the testing channel for application updates. which in turn does not require a license (in the spirit of open source).
The non-Rockstor updates will be available and applied no matter what license is being used as those come from upstream repositories and are driven by the underlying OpenSUSE platform.
If you run the Rockstor instances in a production setting, of course the stable subscription is highly recommended.