Is KJFK being worked on, for an update? Or will that happen in the close future?
That depends how you define "close"...the team that did JFK is currently involved in CYVR and will surely not work at JFK before CYVR is released, which should happen sometime in the summer, let's say August. After that date, we'll start discussing how to handle JFK.
If the above-mentioned update happens, will it be free for current owners of KJFK? Or they will have to pay again?
They'll have to pay something, for sure. How much, depends how large the update will be and how much work will involve, which is not known or decided yet, and we'll not start discussing it until after CYVR is released. Perhaps, we might a forum poll, asking users what kind of update they'll likely have, knowing that the larger will be, the higher the price.
Of course, it won't please everybody: I guess that someone that bought JFK in 2008 when it was released, wouldn't mind buying it again, but it might be different for someone that bought it today.
In any case, in the worse possible situation, with a very large updated, there WILL at least be some kind of discount for current JFK owners, this is a very different case than with Cloud9 KLAX vs FSDT KLAX: there we didn't have both technical and legal means to allow a discount, since Cloud9 was a different company with different accounting and the IP of the scenery is still theirs and we remade the scenery entirely from scratch anyway.
In this case, since we are discussing an update to an FSDT product, we can opt for any solution: we don't are not forced to redo the whole scenery from scratch and we can do any kind of upgrade price.