Still no change on the
product page that
@GOS linked to, and no "more information," either.
(Four weeks is stretching the limits of "soon," if you ask me.)
Hejira is my favorite Joni Mitchell album, but with two copies of it in my collection already, I can't see spending 30 bucks on an SACD when the best existing masterings are fine and an Atmos version will likely be out next year. (Ditto for the other five titles.)
In the meantime,
Pitchfork has just published a thorough reappraisal:
https://pitchfork.com/reviews/albums/joni-mitchell-hejira/