I need to create a few scenery add-ons for an existing airport to facilitate some testing that we are doing on our sim. I am in the process of purchasing P3d v2, but the simulator we are testing is running P3d v1.21. Will the scenery work if I develop it in v2 and then try to run it on v1.21, or do I have to purchase v1.21?

Well I found a location to download the P3d V1.2 SDK, but I had to go outside the P3d website to do so. It doesn't look like the Prepar3d site offers any way to download older versions of the SDK and they haven't contacted me back when I made an inquiry through their website.