According to Apple:
iTunes is now designed to work with HomePod. Use the improved AirPlay menu to choose HomePod and control what plays next with your Apple Music subscription.
Aside from updates to the HomePod, the change log in the App Store does not mention much else. The update is available on the Mac App Store, as well as via the Apple Software update on Windows.
Earlier today, Apple announced that HomePod pre-orders would go live this Friday, with the official release being February 9th. Since then, we’ve received updates on iOS, tvOS, macOS, watchOS, and now iTunes that support the upcoming smart speaker.