An update is coming September 30. Another "Later this Fall".
Looking through the list of new features, only the radio stations update is listed as September 30th. Support for multiple users, Hand Off and ambient sounds are shown as "Coming later this fall". I already have radio stations enabled which seems like something server side. User support and Hand Off are features that need to be built into the operating system and that's not coming this month. I wouldn't wait standing up for the iOS13 HomePod update.