audioOS 9.9.15.1 (build 19J572) is an official Apple over-the-air update for the HomePod, released on 2021-10-25T17:12:19Z. The update package is 1.12 GB. This is a delta (partial) update that requires 14.2.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 021cad8ad79dead632a0e906a67030d3717fed41.zip.