A Japanese job listing has generated some interest.
Final Fantasy XV was released last year after a full decade of waiting, and now we have DLC to look forward to, expanding the already huge adventure even further. It seems that may not be everything Square Enix is working on in regards to Final Fantasy, however, as judging from a new advert on a Japanese recruitment site, a Japanese company is looking for help with pre-production on a new game - and it very much sounds like Final Fantasy.
The anonymous developer is searching for a 2D Artist to work on a "Super-Famous RPG Series" with "a large number of million-sellers" (that also includes online games). Not only that, but the location of the headquarters also seems to match Square Enix perfectly.
If this is indeed the first signs of Final Fantasy XVI, it's likely years away, considering that this is for pre-production stuff, but a lot in this points towards this being a Final Fantasy game. This isn't officially confirmed, though, so take it with a healthy pinch of salt.