audioOS 12.0 (build 16A366) is an official Apple over-the-air update for the HomePod, released on 2018-09-17T17:11:54Z. The update package is 1.4 GB. This is a delta (partial) update that requires 11.3 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 2edbaeb2fa12f68fd9c9e5c2861ccdbb8a9e42b0.zip.