Discontinued Door View Peephole camera

Before purchasing the Peephole camera I had a standard old fashioned doorbell as well as a knocker and a peephole. As I now work at home I was discovering just how many mail and delivery services refuse to use a doorbell and instead knock the door, this lead to many missed deliveries as I never heard the knock. So the Door View camera with it's knock detection was the perfect solution. It has indeed solved my issue and in the first few weeks of use it was amusing to watch videos of delivery drivers instinctively going to use the knocker, seeing the doorbell where is used to be and still deciding to knock the door rather than push the button. Unfortunately it now seems that this device with it's very unique and extremely useful feature has been discontinued and nothing else on the market appears to offer knock sensor. I feel Ring have definitely missed an opportunity and I worry what will happen when I need to replace my unit.