I bought this marvel of simulation back in 2016 for XP10 I think, I don't remember if I had to pay for the upgrade to XP11, I definitely would have, and paying $15 for the upgrade to XP12 still seems like a gift to me. It's one of the planes that I have most enjoyed ever flying by hand, I am not a pilot in real life and I cannot speak with knowledge of the facts, but I have been in flight simulation for many years, I started with a Spectrum 48K and Spitfire 40, and the feeling that you are flying a machine that weighs many tons and has a lot of inertia, I have not achieved it with any other aircraft of its class. Perhaps I do not know how to explain well what I mean, English is not my language and I have to use a translator ,sorry.
In short, if you have it and have enjoyed it, $15 dollars is nothing and if you don't have it but you like these monsters of the air, don't hesitate, you would be missing one of the best, if not the best in its category.