A shared rehearsal tool could connect the next session to a working set list and the songs needing attention. Musicians would see which versions and arrangements the band has agreed to use.
Song notes need version history and clear editing permissions. A private rehearsal recording should not become publicly available by accident. Set lists could preserve performance order while letting members prepare individual notes without overwriting the band's agreed arrangement.
Start with one rehearsal cycle and test changes between rehearsal and show day. Include transposed songs, alternative endings and a last-minute substitute. Keep copyright and recording permissions in mind when sharing material. The aim is a dependable source for the band's own working information, rather than another unstructured message stream.
Related reading: ListnIN: How a Live Music Streaming App Connects Artists and Fans.