Are newer versions of Nik Collection not backwards compatible?

I always save my Nik Collection adjustments as smart filters so that I can go back to past edits and see what I’ve done to a particular file. Today I tried to open a couple layers in an older file made with Analog Efex 2 and Color Efex 4. Photoshop doesn’t even seem to know that Nik Collection 6 is the appropriate filter set to use. It leads me to wonder if DxO has at some point abandoned backwards compatibility with new versions of the Nik Collection. I hope I’m just doing something wrong. Anyone have any experience with this? Thanks.

I do the same. I recollect coming across that a while ago.

Also, the .dop file from some older PL version is no longer readable. DXO figured it out, the syntax of one command changed from a single quote to a double (or vice versa).

Both are a PITA and show DXO is not really concerned about usability and long-term use of their products. “Just make the user redo their work…”

Richard