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 2.52 GB. This is a delta (partial) update that requires 11.2.5 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 81faea76b6c5e3277797ca8e65552d241117488f.zip.