audioOS 9.9.15.1 (build 19J572) is an official Apple over-the-air update for the HomePod mini, released on 2021-10-25T17:12:30Z. The update package is 320.53 MB. This is a delta (partial) update that requires 15.0 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 62876bc9310caa87eeecfe0c0e3e2b6f269b9d0b.zip.