https://techcrunch.com/2020/09/14/europe-starts-testing-app-interoperability-service-to-power-cross-border-covid-19-exposure-alerts/

The European Commission has begun testing backend infrastructure that’s needed to make national coronavirus contacts tracing apps interoperate across the bloc’s internal borders.

It’s kicked off test runs between the backend servers of the official apps from the Czech Republic, Denmark, Germany, Ireland, Italy and Latvia, and the newly established gateway server — which is being developed and set up by T-Systems and SAP, and will be operated from the Commission’s data centre in Luxembourg, it said today.