How to use CATIA downward compatibility?

[@DmitryIliyn]

Thank you for the tutorial. Is there a way to convert an assembly?

[@deeya]

Save As STP in the higher version, and load it into the lower version.
Less effort, same results.

[@Piknockyou]

you've got a dumb solid at the end.
how does that help at all if no features are preserved?

[@BrianDo_CADCAE]

It only effective for Solid
So how about Surface