I believe this could be at least 2, maybe 3 years down the road. I believe the 3 and Y will continue to get the current cells until the process is perfected and capacity is built up to first put them in the S, X and the Truck and they will need a lot of the for the trucks.
I would love to see this be different and all cars be upgraded, but we already know from battery day that production is constrained and they are still perfecting the method.
This could also be used as a differentiator between the 3/Y and the S/X, maybe they never put the new cell in them if they can continue to squeeze gains out of the current cell, they just use those since there is already a huge investment in Reno to make those cells. They have to make enough of them to pay for the investment, and that could likely be several more years.