Over the years Ash's appearance has changed. In next year's Pokemon anime movie, the eternal 10-year-old will once again look different.
— まほろ (@maboroshi_mochi) July 11, 2017
Yet, Ash still looked different in last year's feature film, and next year's motion picture will bring further changes.
See what I mean?
OLM, which has done the Pokemon anime since 1997, is making the feature with WIT Studio, best known for the Attack on Titan anime. Obviously, that could explain Ash's new look, which will hit Japanese theatres 13 July 2018.