The calendar includes the full calendar of feast and saints. It does not require internet connection, so it will display the feast, or the saint of the day, even if you are on Sinai or Mount Athos :-) The application is solely in Chinese and can display both the old (Julian) and the new (Gregorian) calendar (there is a setting for the Calendar style). Fasting rules are also displayed, but you are kindly asked not too rely too much on them, they are accurate, but you should consult your priest