The history of Final Fantasy XIV is a troubled one. The game originally released in 2010 after roughly 6 years of development, but was met by stark criticism from industry media media and fans alike. Square Enix admitted to facing technical troubles during development, and not having done diligent research on how the MMO genre had really evolved with time.
Square Enix was apparently not satisfied with the game themselves, because three years later we would see the rise of Final Fantasy XIV: A realm reborn. More than just some simple polish and fixes, A realm reborn came with a completely new game engine altogether. The game has also received post release patches, fixing problems and introducing new content.