The least PDX could do is pull their converter out of the store, or have a full disclosure in bold letters on its page that it only works with older versions of both games.
As it is, it's really disingenuous to continuing selling it as a product, have some decency please.
It may have been an oversight at first, but it's been pointed out many times over the years and yet nothing has been done, so it's safe to assume the company is aware and deliberately decided it's fine to keep at it.
In the end, the only thing the community can do is heavily advise everyone to not buy this DLC.