The spec seems nice, but we need a unique app with a unique set of "diagnosis servers". When you take an international flight with one or multiple connections y

The spec seems nice, but we need a unique app with a unique set of "diagnosis servers". When you take an international flight with one or multiple connections you are in contact with people from many different countries, should you install all the available contact tracing app available on the app store ? If you have one app per country, you could have the "diagnosis servers" of all the countries federate and exchange data, but in the end it's easier and more effective to have 1 official open-source app from say the WHO.