Happy Scale, a weight tracking app I really enjoy, had the opposite example: I bought a full license for some bucks some years ago, and later they decided to switch to a subscription based model to ensure funding.
Instead of going the "hey, here is a new version of the app, you need to subscribe now", they explicitly included a thank-you note directed at everyone that bought the "Premium In-App Purchase" at the beginning, stating that nothing will change for existing Premium Users, that invested in the app right from the start.
I definitely share the tone of the article, and cannot understand the reasoning behind such a decision. The fact that I read "MandyCam" instead of "ManyCam" at first, and was wondering what that kind of article is doing here, is just the anecdotal cherry on top.