audioOS 9.9.18.4 (build 22L255) is an official Apple over-the-air update for the HomePod, released on 2025-03-31T17:29:31Z. The update package is 1.76 GB. This is a delta (partial) update that requires 15.1.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 6fff91ef7402493241ba08dce2cab37d1e011044.zip.