No official statements that I'm aware of on that subject; but if history holds true, it's likely that existing customers will have some upgrade options available to them. That was the case for Wildblue users, when ViaSat-1 was finally launched (and put into service after launch) - could stay on Wildblue or switch to Exede and it required a "new" install if switching.
P.S. However, I'm already planning what trees I need to cut down since the dish will be pointed more south than south west ;)
Twice the data capacity but much more geographic coverage. These satellites are dumb "bent pipes". New satellites don't really add new technical capabilities, that is the domain of the ground stations, user terminals and network engineers. Data plans and features are the domain of the marketeers and cost analysts. Hard to say. Time is the ultimate revelator.