Glen.Maduke, V10 A/C CAN be flow in V11 but you must load them into PlaneMaker and then save it as a V11 A/C. There are some incompatibilities that can be easy or hard to remedy; the worst one is the cockpit.
In one A/C I had to delete the whole dash to get the system to stop telling me I had a GPS compatibility issues, even after I had deleted same. On a PC you hit control-A to select all items, the hit the scissor icon. I found it best to start over with the 3D dash.
The 'copy a dash from another (V11) A/C' is also problematic during my updates to V11. Not sure why.
While V11 is conceivably a much better platform there are many things I find irritating that were simple in V-10. This A/C updating is just one of them and should have been simplified by the programmers before releasing this iteration.