You are all quite correct , updates were / are not available beyond 2016.
My V6s registered on the 27 of November 2016 (MY 17) has no updates available.
I have checked with the producers of the actual mapping system who say that it is up to Jaguar to continue to pay the licence, in which case they could continue to provide updates as they do for other makes of car,.
I had long discussions with jaguar about the situation who in the end sent me £300 to buy a Sat Nav. which whilst welcome peeved me as I had already parted with some £75k to buy the car.