I just recently upgraded from OF 3 Pro to 4 Pro and I’m loving it! There are a few notable bugs but I trust those will be ironed out soon. I’m wondering though if Outliner will be updated to be “universal” like OF 4 is where buying a copy means you’ve purchased for all Mac, iPhone, and iPad platforms. I like that.
(Hard to believe that I’ve been with OF since v2 Pro and I’ve upgraded each time!)
I would love to see OmniOutliner become universal as well. Additionally, I believe it would be fantastic to have the new SwiftUI framework implemented across all platforms.
I believe that already is the case with OmniOutliner 5. The subscription page includes an option to purchase a single subscription that covers Mac/iPhone/iPad.