The world is quietly, tensely waiting as J.K. Rowling finishes off her screenplay for Fantastic Beasts 2.
Or, could Fantastic Beasts 2 somehow provide a link between the Obscurus and the Dementors, both as representations of pure unhapiness?
That said, Fantastic Beasts saw an entity notably similar to the Dementor come into play: the Obscurus, or the manifestation of the repressed energy of a magical child in the form of a dark, violent force.
If Newt’s use of his Patronus is somehow a major plot point for Fantastic Beasts 2, that would presumably involve him coming face-to-face with a Dementor.