@jrnichols to my knowledge there is no copyright on this name for Apple. Medical ID on iOS was released in September 2014, my app was first launched in June 2014, ...
Besides, in terms of features, UI, etc. the app is different and does not target the same platform.
The premium version is there to pay the different fees I have to maintain the app (domain name, Firebase, translation in other languages, etc.). It is far from paying bills.