Ruling on one who missed fasting in several Ramadans and did not know she had to make them up

Question: A woman was in the early days of her youth and did not know that a menstruating woman must make up the fast. She continued for about ten years, then she learned of this afterward. Now she is old in age. Does she make up what she owes by fasting now? Or what does she do?

Answer: She must make up all the days she missed, and she must intend to make up the days of each year before the year that follows it. She must feed one poor person for every day, half a sa' (a dry measure of about 3 kg) of the local staple food, if she is able to feed them. If she is poor and unable to feed them, the feeding is dropped from her. If she is unable to fast due to her old age, feeding them is sufficient for her. And success is from Allah.