The HomePod has so far been running a cut down version of iOS which Apple refers to as HomePod software. However, with the recent HomePod Software 13.4 update, Apple has made a major underlying change to how its smart speaker works. The HomePod OS is now based on tvOS instead of iOS.
While tvOS itself is also based on iOS, there are some major changes made to its base since it is meant to run on Apple TV — a device that is always connected to a power source. In terms of experience, HomePod owners are not going to experience any changes after updating their smart speaker to 13.4.
9to5Mac speculates that the underlying change from Apple will save the company from additional work that it might have to do for running iOS on the HomePod from a power consumption viewpoint. Since the HomePod is always connected to a power source, it does not need similar power management as iOS devices. By moving the HomePod OS base to tvOS, Apple is saving itself some additional work here.
The publication also speculates that Apple could possibly drop support for the A8 chip with iOS 14, the same chip that powers the HomePod. The fourth-generation Apple TV is also powered by an A8 chip and it is likely to get the tvOS 14 update this year. So, since Apple intends to keep updating the HomePod for a longer period of time, it makes sense for it to update switch the base of the HomePod OS to tvOS.
Perhaps, Apple could also allow the HomePod to act as a native speaker for Apple TV with this switch. While this is possible right now as well, it requires one to make the selection every time they turn on their Apple TV.
Additionally, HomePod Software 13.4 also refers to at least two new smart speakers from Apple that are in development. The details about the speakers could not be discovered in the firmware, but it does confirm another report about Apple working on a smaller HomePod due to release later this year.[Via 9to5Mac]