Hi,
If a operating system is not supported by a product, then you are obligated to state this fact in the products description. Not doing so is malicious as you are taking their money and there is no refunds, some of these planes are $40, that is a lot of money to some people.
There are products on your store that use a API not supported on all versions of X-Plane on the platforms that X-Plane can run on.
x-plane.org, always states when a operating system or version of X-plane is not compatible with a plane or plugin on their store.
I will not be buying any other products from your store until this is done, I am not trying to be rude but you cannot expect people not to complain after spending money on something to find out afterwards something that should have been stated on the products description. Some of those planes look really nice but for now I will be sticking with payware from other sites.
Regards, Jake.