The Corona-Warning App have been downloaded, according to the Robert Koch Institute, yet more than 16 million Germans. Users should get warnings when they are encountered one of the Infected. But how does this work for vacationers in the European countries?

Official Corona Apps, there is also in many neighboring countries. Denmark, France and Austria, for example, also rely on the digital alert systems. "There are between the individual national Apps currently, however, there is no possibility of the data exchange," explains Patrick Bellmer by the IT specialist portal "Heise Online" in an interview with the dpa-themed service.

so What to do as a tourist? A perfect solution Bellmer, according to - just if the Apps are not parallel to each other. "It depends on the duration of the stay. If I'm four weeks in Denmark, where, you know, it is relatively long, no matter what is now in Germany, can switch."

In the case of shorter stays, there is one other possibility: Maybe an old Smartphone, you can use to download the foreign App on it. Another solution is with the Partner split, so Bellmer. So one can use the German App, and the other the country of destination.

Technically, it is possible that the German App communicate with the Danish or French application. The German developer had planned for a corresponding function, says Bellmer. It was unclear, however, exactly when this happens.

Christin Klose/dpa-tmn CHIP Corona

if you want to use in the holiday destination of the Warning, the App should inform themselves with the competent authorities. On the website of the respective Ministry of health, information and Links to the official Apps are usually found.

"is The prerequisite for the use that the country has made its own App in the German App Store or Google Play Store, as well," says Bellmer. German mobile would users not have access to the French Stores. The German App is only available in certain other countries.

Two Apps do not always parallel usable

"In the Warning the Apps, there are two approaches: The decentralised approach comes about in the German and Danish App to use", Bellmer. "A data takes place via a Central Server, the decryption of the data happens on the Smartphone of the user."

But there is a Problem: Two Warning Apps with a decentralized System can not run in parallel on a cell phone, because the so-called Google-Apple-required Protocol. This is the interface between the technology of the smartphone and the App. You can, for example, that is permanently a Bluetooth Signal is sent, as the expert explained.

"In Denmark you can't leave at the same time the German and the Danish App will run," says Bellmer. "If, however, after two weeks of vacation back in Germany and on the German App switching, you will no longer be notified of risk encounters in Denmark. If it is turned off and Vice versa, the German App, you get no more information from Germany."

This Problem has not, according to the expert, in the case of countries with centrally controlled Apps such as France. This would not be claiming the Google-Apple Protocol. How an App is controlled, can be found in the App Store or Google Play Store. There also stand, in which languages is the App available.

"in Principle, the data protection policy when the Central System is slightly weaker than in the decentralized System, because all data are stored on a Central Server," says Bellmer. "This is not the case in Germany. What exactly is stored in data, but always from the respective country."

*The post "vacation in Europe: What is a foreign Corona-Warning-App" will be published by chip.de. Contact with the executives here.