That's a pretty disappointing answer.
Finding out that my few hundred dollars worth of recently purchased aircraft can't be used on XP10 will be enough for me to avoid X-Plane in future.
I'd like to think your answer is a guess and not from an official source, can you advise which it is?
I think the safest bet is to hold off in XP11 until Carenado confirm i'll be able to use my existing DLC.