When did this happen?
PS4 support was dropped with Stormblood's release. Among the many reasons for doing so was that the console didn't have enough memory to show all UI elements at the same time, so when using certain features, like the Focus Target display, the game would have to hide other UI elements like the xp bar or other things in order to display it due to lack of memory. They couldn't expand or add new features to the UI because they wouldn't be able to do it on the PS4.


FFXI worked on PS3.
News to me, I thought ps3 didn't have backwards compatibility because of that fancypants processor they made for it that nothing else ever used