I suspect any updates to HomePod will be virtually silent -- Apple will (eventually) update the CPU or make small design tweaks but won't make a big deal about it and just refer to it as HomePod (summer 2020) or something like that.
I kind of want one, but I think my wife would get annoyed at yet another voice-activated assistant that doesn't do what she wants anyway... Alexa for some reason never answers her correctly (I think it must be something odd regarding a combination of the pitch of her voice, the microphones, the location of the device, etc., because it works fine for me), and she hasn't really taken to using the Google Home mini ("Alexa..." is kind of second nature; "Hey Google..." I guess for her is extra work).