Originally Posted by
LineageRazor
In FFXI, SE decided not to make the "Seekers of Adoulin" expansion available for PS2 in most parts of the world. I had the game both on PC and PS2, and so was only able to install that expansion on PC. If I logged off in an Adoulin area, and attempted to log in on PS2 - I would get an error. It was impossible to log into the game on PS2, if my character was currently in an Adoulin area.
It is possible that something similar may happen for Heavensward. If your character is in Ishgard, and you try to log in on a machine that does not have Heavensward installed, you may not be able to log in at all.