@GMRaphi The new stuff is supposed to be 5e-compatible, my investment in #OneDnD probably depends on how easy it'll be to adapt the stuff from 5e to One.
Also, One D&D is apparently a working title and they're planning to name the new stuf... D&D 5e (2024). I find thay pretty confusing, but I guess that's a sign that there are serious plans for huaranteeing compatibility... We'll see, I guess.