Православный календарь, developed by the Orthodox Church in Hong Kong 香港聖彼得聖保羅東正教堂, is an Android-based application that offers an extensive library of religious texts and a comprehensive calendar. This app provides a range of features, including the ability to view icons and Gospel readings for each day, as well as troparia and kondakia for the twelve great feasts, saints, and days of the week (with audio). Users can also set reminders for holidays and choose the degree of fasting. The library includes the full text of the Bible, prayer books, and commentary on All-Night Vigil and the Divine Liturgy. The app's source code is also available on Github for those interested in learning more about the development process.