https://techcrunch.com/2020/06/16/eu-states-agree-a-tech-spec-for-national-coronavirus-apps-to-work-across-borders/

European Union countries and the Commission have agreed on a technical framework to enable regional coronavirus contacts tracing apps to work across national borders.

A number of European countries have launched contacts tracing apps at this point, with the aim of leveraging smartphone technologies in the fight against COVID-19, but none of these apps can yet work across national borders.