FeiertageDEU is a free Android application developed by Matthias Glemser, categorized under Business & Productivity. The app calculates all statutory holidays for Germany and some religious holidays and other special days such as DST beginning, summer solstice, etc. It covers the years between 1583 and 2800 and considers the validity of the holidays. For holidays that do not apply to all states, the app displays them accordingly. However, historical changes such as establishment, merger, etc. are not considered.

FeiertageDEU also provides features such as the acquisition of the calculated days in the calendar, indicating the daily numbers and calendar weeks. Moreover, the colors of the date list can be customized user-defined. Though the app provides information on federal states based on the current conditions, it does not consider historical changes.

Overall, FeiertageDEU is a useful app for anyone living in Germany, making it easier to keep track of all the holidays and special days in the country.