My biggest concern would be lock-in to the license, not lock-in to an old Python version. The nominal cost to get up-to-date right now doesn't guarantee me perpetual updates, right?

I'm also suspect of the misleading presentation on the landing page; nothing in the "Open Source" section says anything about the fact that the author has resolved to let the Open Source version effectively die, while up-selling existing users to the paid version. I respect the approach, and you deserve to be payed for the work, but it would be good to not effectively lie on the home page.

thanks for the clarification