The official website for the film BanG Dream! Episode of Roselia has just announced the release date, which will be April 23, 2021 .
The second film, BanG Dream! Episode of Roselia II: Song I am ., will also be released next year.
The first 13-episode season of BanG Dream! premiered in January 2017, with Anime Network Online and Crunchyroll streaming the first season as it aired in Japan. The anime's second season premiered in January 2019. Sentai Filmworks licensed the anime, and HIDIVE and Crunchyroll streamed the series as it aired.
Source: ANN