They don't "give" you the new version. They take away the app you paid "once", and provide you with a version with an expire date. So you have no choice. You either pay them, again, or lose access to the v2 (subscription based) app.
I don't mind paying for good software, I even think Hallide is worth $60. But I won't make the same mistake again. So best of luck Lux! I really wish you all the success. If you treat your customers right this time.
That is "forever updates" = no but "take away what you had" also = no. It was a period of updates with a dropoff date of where you left off. This lines up with my expectations of a one time purchase in that I'm not expecting 50 years of feature updates when buying software just because they haven't went out of business yet I'm just expecting I keep the feature access I have at the end, which is what these posts from many different folks are all claiming.
I'm not sure which group the Halide changes mentioned above fell into but just on the general topic I think it's a fair expectation.