With the latest update for the Apple HomePod, version 13.4, the OS of the smart speaker has been ported from iOS to tvOS. 9to5Mac speculates that this means, among other things, that the HomePod will continue to be supported for the time being and that a new HomePod is on the way.
The move to tvOS doesn’t change the functionality of the device for the user for the time being, but under the hood tvOS has different APIs than iOS, for example. At its core, though, tvOS is still based on iOS. The Apple TV also runs on tvOS.
9to5Mac further speculates that the switch has to do with support; the HomePod runs on an Apple A8 chip, which will no longer be supported in the next version of iOS. This includes the iPhone 6 and 6 Plus, the iPad Air 2 and the iPad mini 4.
According to research by 9to5Mac, but also Bloomberg, this change also has to do with a possible arrival of a HomePod mini, but also of a new Apple TV.