Just a heads up for everybody who has the same problem as me with the presence detection via router. I don’t know if this is the right place for it, but I think this info should be shared.
Currently I’m using my fritzbox to detect whether my iPhone is logged into the wifi (considered home) or not (considered away).
So far so good - starting yesterday it did not work anymore after the update to iOS14.
The problem is, that starting with iOS14 Apple introduced a new feature to reduce tracking via WiFi. In order for the presence service to work properly again, you need to go to Settings > WiFi > Click on the blue (i) on the right side next to your home Wifi > Disable the option “Private Adress”
Private Address gives your device randomly a new Mac Adress which results in a new device under known devices everytime this address is changed. In my example I had iPhone, iPhone_2, iPhone_3 in my “known_devices.yaml” and the original entry of my iPhone was not detected as the mac address changed.
I hope I can help some people to solve a similar problem a little bit faster with this guide.