The new HomePod software will be installed automatically on the HomePod after you update to iOS 12.2, but you can also manually update and check your software version by following the instructions in our HomePod software how to.
According to the release notes for the update, the new software for the HomePod is minor in scale and designed specifically for university or enterprise users.
iOS 12.2 includes support for joining most enterprise or university campus 802.1x networks that do not require unique credentials to join.There are no other features that appear to be included in the HomePod update. Right now, the HomePod is available in the United States, UK, Australia, Canada, France, Germany, Spain, Mexico, China, and Hong Kong. For more details, make sure to check out our HomePod roundup.