audioOS 9.9.12.3 (build 16F156) is an official Apple over-the-air update for the HomePod, released on 2019-05-13T17:18:14Z. The update package is 1.42 GB. This is a delta (partial) update that requires 11.4 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: a660ca5fca3e38d0e124ef634d7b38973f639a06.zip.