Vertretungsplan.app is a free Android™-based application developed by TK-Schulsoftware GmbH Co. KG. It is designed to provide an easy and convenient way for students to access the substitution plan or supplier plan of many German and Austrian schools using their smartphones or tablets. The app boasts a sleek and user-friendly design that is both comfortable and pleasing to the eyes.

With Vertretungsplan.app, you can stay up-to-date with the latest changes to your class schedule. You will be notified automatically within a few minutes of any changes to your selected class. The app also offers an in-app purchase of the "Vertretungsplan Pro" version that provides additional features like selecting multiple classes simultaneously, teacher representation plans (for some schools), and the ability to customize the colors of the substitutes and the widget.

Note that the app only provides information provided by the schools and is not guaranteed. The developer also cannot guarantee the reliability of notifications. For more information, visit their website or social media pages.