audioOS 9.9.18.4 (build 22L255) is an official Apple over-the-air update for the HomePod, released on 2025-03-31T17:29:30Z. The update package is 1.76 GB. This is a delta (partial) update that requires 15.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 97cd27eaa2e4f29bf42dbd2cbffb5d70d7084327.zip.