Update: I've heard news from Jonochrome's twitter that the new game is cancelled.
He is very stressed, so please give him some breathing space.
Jonochrome (the maker of ONAF) has announced that he might make a third game for the Flumpty series.
Here's a teaser for the third game.
Here is a vlog by Jonochrome himself talking about why he is making a new game based on his "one night at flumpty's" series.
He mentions that he wants to make a third game, but isn't 100% sure if he is going to finish it. He talks a bit about making other games too.
Also Jonochrome mentions that the game will have 5-7 nights.