audioOS 12.1.1 (build 16C50) is an official Apple over-the-air update for the HomePod, released on 2018-12-05T18:07:02Z. 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: a53ff89470f734e3168a9003f8e1352fc4bc9f10.zip.