High-Definition DVD question

[Carol]

I asked this question on the movie list but no one answered it, so I'm
repeating it here:

Does anyone know whether the OoP film will come out in standard DVD
format before it comes out as a high-definition DVD? Also, can you
play a high-definition DVD on a standard DVD player, or will viewers be
forced to follow along with the new technology as they had to do when
DVDs replaced VHS tapes?

Carol, who hates being forced to buy new equipment every time
technology is "improved"