I recently started using this app and am finding it very helpful. It is available on iOS and Android.
Orthodox Calendar – A good and simple app that defaults to the Julian (Old) Calendar. It contains the lives of the saints, fasting regulations, daily tropars and kondaks, and the daily scriptures. For the lives of the saints, it usually shares several saints per day with lengthy biographies. The calendar is adjustable to select any day of the year (if you’re on the New Calendar, just go forward thirteen days). It utilizes liturgical language (Thee/Thou) for the daily troparia.