It seems that the upcoming second Sound! Euphonium compilation film, and the only upcoming film from the series. This is because the staff revealed not one, but two new movies during an event in Kyoto. They also streamed the announcement video for these two films, which also talks about the second compilation film.
K-On and A Silent Voice’s Naoko Yamada directs the first of these two new films, while the TV anime’s Tatsuya Ishihara will be the chief director for the second one. The first film will follow Nozomi Kasaki and Mizore Yoroizuka, while the second film will follow Kumiko as a second year.
The staff also revealed new details about the second Sound Euphonium compilation film, Gekijou-ban Hibike! Euphonium: Todoketai Melody. They revealed that the film will premiere on 30th September, and also revealed a new teaser video:
The anime’s staff also revealed a brand new visual for the second compilation film, which of course features Kumiko.
Expect Kyoto Animation to reveal more details about these three films soon.
source: Sound Euphonium official