I don't believe this would fit to what I understand is Boonex' plan. Boonex Pro is basically 7.2 and U is a revamped 8.0 that doesn't have all the features of the Pro YET.

So I guess eventually Dolphin U will get all the features of the Pro as they're progresively ported. So maybe then Boonex will replace Dolphin Pro with an 8.0 branch based code and a license which will have all the plug-ins as well as the mobile app for Premium customers.

So Pro is the current version and U is the future see more but is far from being finished. Marketing !

It's like if Apple wanted to release the iPhone 6 but they were late so they released the iPhone U instead with new design but without camera or GPS (which would be free add-ons released later) and renamed the iPhone 5S as iPhone Pro. That sounds ridiculous but it's actually what it looks like Boonex is doing right now.