audioOS 9.9.18.1 (build 22J580) is an official Apple over-the-air update for the HomePod (2nd generation), released on 2024-10-28T15:30:29Z. The update package is 976 MB. This is a delta (partial) update that requires 17.5 already installed. This update is currently signed by Apple, so it can be applied from Settings › General › Software Update.

Payload file: a932d91373a3a33ca8ced6c86394bbfe98891e17d8eb70dc908d1f19109f6cea.aea.