X-Plane is incredibly extensible. You can simulate new aircraft, make 3-D models, or even change the functionality of the program in drastic ways.
X-Plane 11.20 is, of course, final! Like all good Klingon software, it was not so much released – rather it escaped captivity, leaving a trail of blood in the path of all whom opposed it.
I am aware of two plugin-related issues we are tracking: