audioOS 9.9.18.4 (build 22L255) is an official Apple over-the-air update for the HomePod (2nd generation), released on 2025-03-31T17:29:49Z. The update package is 1.22 GB. This is a delta (partial) update that requires 17.4 already installed. This update is currently signed by Apple, so it can be applied from Settings › General › Software Update.

Payload file: 216dbff280671a48d08bbe9564885ceaa237953a822dcd5c685142262460ef25.aea.