The Apostolic Exarchate of Serbia practices liturgy in the Slavonic form of Byzantine Rite and uses the Old Church Slavonic language and the Cyrillic alphabet. Adherents of the Eastern Catholic Byzantine Rite in Serbia are mainly Rusyns,[1] Ukrainians, and Rumanians[citation needed]. In 2016, the Apostolic Exarchate for Serbia had 21 parishes with 21,845 faithful and 21 priests.[2]