I'd imagine that right now the staff are busy with the new update, and when the update is released the Farm World would be reset. Although since there are new staff it may be reset beforehand. Just speculation.
As for what happens, The world is reset back to how it was originally, removing all destruction, construction and the likes. Not sure If anything about the world(as in, the original) would change though.
Again these are just my guesses since there's been no information about how the resets work, or any resets at all since Lucenria's release. tl;dr No ETA, Possibly when the new update arrives.
@FrankieT_193@Cloaked Occultist I will be sure to bring this up to @LadyHope as Krantz and myself have realized this I would like to say we will most likely do it during the time of the update just to keep things fresh for afterward.