Can older versions of AI be used in a newer YGOPro? Kind of taking .ydk and .luas from older AIs decks and put it into the YGOPro AI folder
Probably not, the AI interface has undergone massive changes over the years. Most versions won't be compatible and probably produce errors.

Feel free to try old AI files on your end. If you find working files, report back and I might add them.

If you are referring to older versions of currently existing decks, you can just get the old decklists here . They should still work with the current AI script, to some degree. Probably not all of the decks, and probably not exactly as they used to.
Youre not talking about ai template scripts?
Yeah, I thought about taking, by example, "Shaddoll.ydk" and "Shaddoll.lua" from AI 0.26 and just throw it into the AI folder so it could handle it the same way it used to do. But it works terrible ._. Anyways, thanks for answering, and good luck working on the new AI, that's the best thing in the world, I'm a big fan of it
And, off-topic, does Percy think about implementing something like ygopro2 "smart helper"? It would be reaaally useful