Looks like that early theater listing for the first part of the Fate/stay night[Heaven's Feel] anime movie trilogy wasn't quite right. In time to be unveiled at AnimeJapan, the slow drip of information about the project has finally yielded a release date. Part I, now subtitled "Presage Flow" will open on October 14th, 2017.
The trilogy of anime movies adapting the Type-Moon visual novel route in which Sakura Matō is the heroine features Tomonori Sudou, animation director/character designer of ufotable's Unlimited Blade Works TV anime, as director. Yuki Kajiura will be composing the music. Tickets went on sale at theaters across Japan on February 18th.