Dashboard, PBX Status, phones is red on my test server. "You are using Unsupported phones or phones with custom templates which may cause issues."
Connected test phones are all up to date and supported. After some digging, I found I had tested a conference phone with a custom template and never deleted it. I'm thinking maybe have the indicator only relate to connected phones and not extensions, or/also have the informational warning possibly list extensions with the violation so we're not looking for a needle in a haystack.