audioOS 9.9.17.0 (build 21J354) is an official Apple over-the-air update for the HomePod (2nd generation), released on 2023-09-18T17:26:45Z. The update package is 1.07 GB. This is a delta (partial) update that requires 16.4 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 03ea77ba17f0843e7ef3e3209ee0bca4aeaf9398.zip.