And you thought it was over with number 3. Developer Scott Cawthon has updated his site with this image, promising a final, forth Freddy's for this halloween.
Cawthon posted a picture of a hat on his site after Freddy's 3 which most people read as a sign he was hanging his up on the series. The third game also had an ending option that suggested a certain amount of closure within its mythology. There's also the recent announcement of a Five Nights at Freddy's movie which also seemed like a good point to move on.
Then the hat disappeared. Everyone started to wonder, and now we know. Question is, will this be a continuation of the three previous games? The monitor watching jump scares were starting to feel a little strained by the end of the last game.