No radical changes in API during so many years in something FF-related? I really doubt that, sadly. IIRC freeman&co checked it, once, and it was totally incompatible, but I may be referring to something only vaguely related, so don't quote me on it.

But, having open backend and "only" frontend" closed, can't we compare how "old" open backend communicate with closed UI, as related to "new" backend API? Or am I missing something?

/Estel