It seems like only a matter of time before Harry Potter and the Cursed Child is made into a movie, but it would need to go through several major plot changes for this format to work. Because the Harry Potter sequel was written to be a stage play, it's of a significantly different flavor than other installments in the franchise. Theatre doesn't follow the same rules as movies, TV shows, or even books, so Harry Potter and the Cursed Child got away with presenting the wizarding world in a different light and even breaking continuity in a way that a film couldn't do.

https://screenrant.com/harry-potter-cursed-child-movie-could-work-plot-changes/