audioOS 9.9.15.4 (build 19L440) is an official Apple over-the-air update for the HomePod, released on 2022-03-14T17:12:32Z. The update package is 461.13 MB. This is a delta (partial) update that requires 15.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 1cf6b5c017420c5d9f3512e4f2b75f608fd4ed14.zip.