Let me address a few of your points that I am able to address
There is no next generation of UBB! The announcement is that it will be a new version of UBB.threads.
From the Announcement:
While the new product was originally designed to replace UBB.classic and UBB.threads, we wound up using much more of the core design of UBB.threads. Thus, we are now considering the new product an upgrade of UBB.threads, rather than a replacement.
My UBB.classic license will end in July and here I stand with the option to extend it, or change to something new...
Just because your Member's Area expires in July doesn't mean that you have to renew on that date. You could wait until the release to renew your Member's Area. This is not the case if you are using a Leased License.
Around the same time and before the big news, Groupee's only response is a message in the board that they offer all users to change product to their hosted solution.
I have not seen such an offer posted. The only thing close to what you are saying is that they were having a chat for those who were interested in changing. They never offered all users to change to the hosted solution.
Why can't I find anything about the next generation UBB on the groupee home page? Don't they want to be related to it or what?
I have so many why, why, why?
They want UBBCentral.com, soon to be UBBThreads.com to be the home for the downloadable products.
But, this leaves more questions, at least for me...
And then again, when? No actual date! Only an alpha release date.
You won't see a release date until closer to the actual release. You cannot predict how many bugs you will squash during a beta period.
What are the future plans for this next generation product?
Groupee tends not to divulge anything beyond what has been announced.