J.K. Rowling has confirmed that Fantastic Beasts 3 will answer fan questions about the Harry Potter prequel series. The second film, Fantastic Beasts: The Crimes of Grindelwald, ended with a stunning scene that left viewers reeling. The revelation that Credence Barebone is really Aurelius Dumbledore, brother of Albus Dumbledore, is one that is difficult to reconcile with the canon.
Rowling has always been a master storyteller, known for the complexity of her world-building and her tremendous attention to detail. That made the Credence twist all the more surprising; there's never been a hint of a fourth Dumbledore in the previous Harry Potter books. Worse still, this sits very uncomfortably indeed alongside the established Harry Potter timeline. By the 1890s, Albus Dumbledore's father had been committed to Azkaban for life imprisonment, and his mother died in 1899. Credence would seem to be far too young to be a Dumbledore. And yet, the script itself strongly implied that this is indeed the case; that's why Fantastic Beasts: The Crimes of Grindelwald introduces the Phoenix legend to the Dumbledore family history.
Rowling is very active indeed on Twitter, and one Harry Potter fan recently asked her to describe Fantastic Beasts 3 in just three words. Rowling responded with a simple sentence: "Answers are given." Although the Credence twist has been treated as something of a plot hole, the reality is that a writer of Rowling's caliber would not have made Credence a Dumbledore if she didn't have a plan to explain how it fits with the established Harry Potter continuity.
This comment fits perfectly with observations from Ezra Miller, the actor who plays Credence. He asked fans to trust J.K. Rowling, and even argued there's been a subtle progression running through the Fantastic Beasts films to date. The first movie was focused on the question of just what Credence is, revealing him to be a powerful Obscurial. The second explained who he is - a Dumbledore. The third, in his view, will explore the most important question - why. He's expecting Fantastic Beasts 3 to reveal why Aurelius was hidden away from the rest of his family, and has never been mentioned in the Dumbledore family tree before now. Given Miller also noted that Rowling chats about plot twists with the actors themselves, it's entirely possible Rowling herself had suggested this to him.
Although a release date has yet to be set for Fantastic Beasts 3, it's generally assumed the film will come out in 2020. There was a two-year gap between Fantastic Beasts and Where to Find Them and Fantastic Beasts: The Crimes of Grindelwald. It's generally assumed Warner Bros. will want that to be the norm.
Source: J.K. Rowling