More than 1.47 million people with a smartphone cannot use the CoronaMelder app, according to figures shared by the Ministry of Health with NU.nl. That's because those devices don't run the necessary version of the Android or iOS mobile operating system.

The CoronaMelder app only works on smartphones with Android 6.0 or higher and iOS 13.5 or higher. The app uses a framework from Google and Apple that only works with those versions of the software.

On smartphones on which the app is installed, signals are exchanged with each other to register proximity. For example, people who may have run a risk of being infected with the corona virus can be warned.

5 percent of Android smartphones and 15 percent of iPhones run an older version of the operating system, on which the app cannot be installed. That equates to 425,000 Android users and 278,000 iPhones owners aged twelve or older. In addition, there are more than 278,000 smartphones with an operating system other than Android or iOS.

"The vast majority of people can use the app," said a health ministry spokesperson. "But the app is an additional tool. The regular source and contact research will not disappear and will remain available to people without the app."

The maximum range of the CoronaMelder app is 12.7 million smartphones. The Ministry of Health announced on Tuesday that the app was downloaded 431,000 times on the first day.