Before a game reaches its final stages, it usually undergoes massive changes on every level. This is a truth that hit the Final Fantasy series very hard in the last decade.
Originally, Final Fantasy Versus XIII was a game set parallel to the Final Fantasy XIII universe and was meant to be a spin-off of sorts, in that it would share the same mythology but would feature different characters and story in a completely different world. It was originally announced for the PlayStation 3 alongside XIII and Agito XIII (which would later become Type-0 and be released for the PSP exclusively in Japan).
Due to problems within Square Enix that required Tabata to take over the project, its development slowed down as the director’s desired mechanics could not be realized with the PlayStation 3. Thus, when Sony showcased their new console to Square Enix, development shifted to the PlayStation 4 and the title was reannounced as Final Fantasy XV, distancing itself from the Fabula Nova Crystallis (the collection comprising Final Fantasy XIII, Final Fantasy Type-0 and, at the time, Final Fantasy Versus XIII).
As Versus XIII was rebuilt in a new engine, rebranded into XV, and its ties to XIII cut, players wondered whether Versus XIII was completely thrown away or if Square Enix still had some of its files lying around.
A picture is circulating the internet that claims to prove that Final Fantasy Versus XIII is alive, and is being remade as a game called “World of Versus” (previously rumored to be a DLC for XV).
Take this rumor with a grain of salt, but some fans are hopeful that this is the real deal. Perhaps an announcement for the title is finally due. Given the success of Final Fantasy XV, it wouldn’t be out of the realm of possibility for Square Enix to try and capitalize on the momentum they have gotten. More updates on this as they become available.