I’m in the same boat. I’m mid-project, and I decide to copy a duplicate into 5.1 - to a point, everything worked as intended, so I kept working on things like foliage. Once I got back into animating and working with my metahumans again, wowee! Arms distorting all over the place, I can’t compile any metahuman BP without warnings about “out of date” and “Degenerated” references.
Even re-downloading the metahumans fresh from the editor doesn’t help - even when I’m going back to 5.0 with the upgraded plugin! I’d like to have a much better roadmap with this DNA stuff as well (why the hell do I need to select a skeletal mesh, like I’m importing an animation?). Why does an upgrade need to disrupt workflow like this?