To be honest, not much is known besides these things:
City-State Aethernets are staying.
Attuned Aetherytes will be reset:Example: In FFXIV: ARR, all players will have unrestricted access to the city-state aethernets, which will render aetherpasses obsolete. Players already in possession of these passes will receive 40,000 gil in compensation (as per the redenomination, 1/10 of the original purchase price). Players who purchased the aetherpasses with company seals will be recompensed in gil.