audioOS 9.9.12.3 (build 16F156) is an official Apple over-the-air update for the HomePod, released on 2019-05-13T17:18:16Z. The update package is 412.16 MB. This is a delta (partial) update that requires 12.1.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 5d3ab84be7b07858ec84c9875d9b2d8214c539f7.zip.