This is actually what the application help says, but Epicor Development confirmed that the system has always worked the same since E9 -
It doesn’t check whether the revision is approved or not; it just replaces everything in both approved and unapproved revisions.
But the Mass Part Replace/Delete should check at the revision level.
It’s almost there. I’m not going to do v1 yet because XML versus JSON … and the ask was about EFx, so v1 doesn’t apply anyway. Just have to get the schemas to load in the body portion of the requests.