Sure, but if that's the case, you should really be pushing new developers away from using the old thing and towards the new thing. Mark it obsolete in the editor. Update your docstrings to point towards the new thing. Maybe even give me a warning in my console if it's really serious.
You might have to use a superseded feature because you're maintaining old code. If Unity cares about backwards compatibility (admittedly, I'm not convinced they do), they need to keep supporting and documenting the old features even as they nudge you away from them.