audioOS 9.9.15.4.1 (build 19L452) is an official Apple over-the-air update for the HomePod, released on 2022-03-31T17:16:00Z. The update package is 537.52 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: ffa4139a5e14b0d39583fd0720e55f34e6fb114b.zip.