I think it's named "Pixelmator Pro" entirely because Mac App Store does not support paid upgrades.<p>Feature-wise Pro is not that major. It has an entirely different UI than Pixelmator 3.6. Long term, maintaining two different apps with very different UIs is not going to work. I wouldn't be surprised if 3.6 remained as last version of non-Pro Pixelmator.<p>So why Pixelmator Pro and not just Pixelmator 4.0?<p>Pixelmator never charged for upgrades on Mac App Store, and as influx of new users inevitably decreases, they need to get more money from existing users. Options: Subscription, In-App Purchases, Leave Mac App Store, or separate new app on the App Store. Maybe Pixelmator 4. Pixelmator Pro sounds better and more worthy of a "new" app purchase.<p>Their messaging around 3.6 is very lacking and confusing, lack of paid upgrades on Mac App Store does explain everything.