I bought and play FFXIV: A Realm Reborn on Steam. Do I need to purchase Heavensward on Steam to upgrade my account?
Global: Yes, you do as the Steam and Windows versions of A Realm Reborn have different play entitlements. The registration code that comes with the purchase of the Steam version of FINAL FANTASY XIV: A Realm Reborn is a Steam-specific play entitlement. If you purchased the game via Steam and set up your service account using the Steam-included code then you cannot use a non-Steam version of Heavensward to add the expansion to your existing account.
http://forum.square-enix.com/ffxiv/t...rs-bonuses-etc

the info is already 2 1/2 months old