GoodNotes Forcing Paid Subscription After One-Time Purchase

I originally purchased GoodNotes because it was offered as a one-time payment app. However, now they are forcing users into an annual subscription under the excuse of a mandatory upgrade. This is completely unfair! When I bought the app, the agreement was for lifetime access, so how is it legal to now demand a yearly fee?

Does this comply with consumer rights and trade laws? If I had known they would switch to a subscription model, I would have chosen a different app. I refuse to be forced into this unjust payment scheme. At the very least, existing users should be allowed to continue using the app without a subscription. I demand that GoodNotes honor its original pricing for previous customers!