Catholic Liturgical Calendar is a free Android application developed by MoonStarInc that helps users find Holy Days and Feasts on the go. It also provides information about the start and end day of Catholic seasons such as Advent, Christmas, Lent, and The Triduum (Good Friday, Holy Saturday, and Easter Sunday).

The app is designed to be user-friendly and dynamic. It calculates the Catholic feasts like Advent start date, Triduum, and Lent for each year. Additionally, it allows users to read daily readings and learn about the Saint of the day. The app is currently available in English, but support for multiple languages will be added soon.

Overall, the Catholic Liturgical Calendar app is an excellent tool for Catholics who want to stay up-to-date with the liturgical calendar and deepen their faith. If you have any feedback or suggestions, the developer encourages you to rate and comment on the app.