Into a bowl, sift together the flour, the baking powder, the baking soda, the sugar, the salt and the cinnamon. Add the butter and blend the mixture until it resembles meal. Stir in the oats and the currants, drained. Add the buttermilk and stir until the mixture just forms a soft sticky dough. Drop the dough by rounded tablespoon onto a buttered baking sheet and bake the biscuits in the middle of a preheated 425 oven for 15 to 17 minutes, or until pale golden. Makes about 16 biscuits.