Juli Clover (no release notes):

HomePod Software 27 adds AirPlay improvements and support for AutoMix when listening to Apple Music.

Ryan Christoffel:

AirPlay improvements may sound like a minor change, but in practice they can make a big difference in connecting quicker than ever to your HomePod. Using the iOS 27 beta, I’ve been pleasantly surprised by how fast and easy it is now to switch playback to and from my iPhone and HomePod.

[…]

There’s no Siri AI available in HomePod 27.

Previously:

• audioOS 26.6
• Siri AI Beta
• audioOS 26