For all those interested in technology, some information about the development of IQ-DUELL®:

IQ-DUELL® was developed with Ionic, a popular framework for app development. The realisation as a progressive web App (PWA) was given preference over native apps for the platforms Android and iOS. PWAs combine the properties of web pages and native apps. They adapt progressively to the respective device and/or the browser used and are called like a web page by entering an URL in the browser and then added to the “home screen” with an icon. Downloading from an app store becomes expendable. Updates are performed automatically. PWAs also save a lot of storage space compared to native apps and have faster loading times.

PWAs also support (web) push notifications, i.e. messages that appear on the screen even when the addressed app is not running at all. That’s the magic of so-called service workers. This is a modern browser technology that uses JavaScript to provide a proxy between the web browser and the server. It is only since iOS 11.3 that service workers are also supported by Apple devices; For this reason, users of iPhones or iPads with older operating systems have to check in IQ-DUELL® themselves, whether they have been challenged for a duel or are in the turn again in an open duel.

If you want to learn more about modern app development, the book Ionic 3 – Attraktive Apps entwickeln für Android, iOS und Windows by Andreas Dormann is recommended.