Orthodox Calendar is a utility tool developed by NeoSphere LLC, available on the iPhone platform. Created with the support of the portal Pravoslavie.ru, this application displays the Orthodox calendar in both the new and old styles, highlighting Easter, major holidays, and fasting days. Users can also explore prayers and icons of saints commemorated on specific days. Additionally, it includes daily thoughts by St. Theophan the Recluse.

One notable feature is the high-quality images of icons and the option to listen to prayer chants, which are streamed from the developer's server. It's important to be aware that data charges may apply based on your mobile operator's tariff.