I upgraded my iPhone and was experiencing problems using the new phone as a presence sensor. I deleted it off my devices and now I can’t add it back. What can I do?
Can you explain what you did exactly? I am unsure what deleted it off my devices means. Deleted the ST app?
In the ST app on the new iPhone, go to Menu > settings and ensure get location from this iPhone is enabled.
On your old iPhone, disable that setting.