audioOS 9.9.18.4 (build 22L255) is an official Apple over-the-air update for the HomePod, released on 2025-03-31T17:29:33Z. The update package is 1.5 GB. This is a delta (partial) update that requires 16.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 1b7d3c5817c6338d8cb5b75294e25400f69882ce.zip.