It was revealed in the final episode of the third season of the BanG Dream! anime that the franchise will receive three films in the next two years.
Therefore, the first two films titled BanG Dream! Episode of Roselia I: Yakusoku and BanG Dream! Episode of Roselia II: Song I am. are planned to be shown in Japanese cinemas in 2021, and BanG Dream! Poppin' Dream! was planned for 2022. Additionally, the franchise's YouTube channel posted a video announcing the films.
Furthermore, the chief director of the three films will be Koudai Kakimoto, who also directed the second and third seasons of the anime. Atsushi Mimura (CG supervisor for the anime's third season) will direct Episode of Roselia , and Masanori Uetaka, who provided the storyboards and directed some episodes of the series, will direct Poppin' Dream! .
Source: ANN