This is what their website says about the paid upgrade:Hmmm. I saw that it had in-app purchases, but didn't dive more into what they were.
If you want to support the app, get Orion Pro: It packs AI upscaling, CRT emulation for retro games, and image adjustments (and whatever else we cook up). It's a one-time upgrade for $5. It unlocks everything. No subscriptions.