ATEM 2M/E Broadcast Panel: Restrictions?

Is there anyone who uses an actual ATEM Constellation HD 4M/E switcher with an old grey 2M/E Broadcast Panel (not the new Advanced Panel)? Does this combination still work (since 8.9 I guess)? And are there any restrictions or features which won't work with this panel? I heard that there is no way to save the buttons setting. But does it keep the last status?
Thanks and best, Thomas

Button setting is saving into panel I think .. Why its not working ?

I don't have a panel yet (only the Constellation HD 4M/E). But I want to clarify if there is an important difference between the new and the old one, and if the old one has major restrictions, before buying a used panel.