audioOS 9.9.18.4 (build 22L255) is an official Apple over-the-air update for the HomePod (2nd generation), released on 2025-03-31T17:29:45Z. The update package is 1.47 GB. This is a delta (partial) update that requires 16.0 already installed. This update is currently signed by Apple, so it can be applied from Settings › General › Software Update.

Payload file: 2f99746f915cf6eace2a3de885089ebe0b6831aead3b9eb06b6035da01b20832.aea.