1. Apple will allow software only solution and supported by Indigo. (Very unlikely with the current licensing limitations Apple is imposing)
2. Some vendor comes up with a certified hardware interface. ( Even more unlikely as they will probably never see a profit based on potential market size.)
3. Enhance/build an updated Indigo iOS app/Apple Watch app that uses the Siri interface interfacing directly to Indigo, bypassing Apple's Home app. I don't know how robust the Siri API is for building voice interfaces but assuming it provides a core functionality to send command to control outputs. Using iOS and Apple Watch (and maybe even Apple TV) you would get an interface directly to Indigo, not the Home app. I'm assuming HomePods would not work unless there is some way to interface them to an iOS app via voice control.
Like many other users HKB has provided a fantanstic level of functionality that I dread seeing going away at some point in the future. At least the approach in #3 could bring back much of the same functionality and more importantly allow Indigo (the company) a lot more control and stability in the process. Plus I don't look forward to telling my 87 year old mother in law she has to start getting out bed to turn the lights out instead of using Siri.
Thoughts/comments?