I had a feeling that it would be easier to tackle this problem before I got too deep into development (unless, of course if that's a bad idea/the hard way, please inform me...). I'm creating my game to be run ideally on DirectX 11, however, I want to offer it on DirectX 10, and I'm unsure if it is worth offering it for DirectX 9 for XP users. I'm not too sure how this fallback even works, as I can't find many articles on the internet. If someone could give me an in-depth article, that would be great.

I've read a little about how since DirectX11 is completely absent on XP, it is hard to even check for support. Someone mentioned having multiple applications for each version, is this a good idea?

Thanks to anyone who can point me in the right direction here.