Check the terms - if you already own them, you're grandfathered into the Connect (highest tier) package for free (for now, at any rate).
I recently got a second hand remarkable, and absolutely love it, but not sure how I feel about them pulling this sneaky (however justified it may be). It's not that my assets are in jeopardy, but I'm slowly developing a whole new workflow, which I don't want upended 12 months from now if they decide to charge everyone...
Is there a good open source alternative?