The World Federation One Stop Fiqh

Ruling 1678

If a person delays keeping the qaḍāʾ fasts of the month of Ramadan for a few years, he must make them up. For the first year’s delay, he must give one mudd of food to a poor person for each missed fast [as kaffārah]; however, for the delay in the later years, there is no obligation for him [to give kaffārah].13

13 For example, if someone has to make up one fast and he delays making it up for three years, he must give one kaffārah [i.e. one mudd of food] to a poor person, not three kaffārahs.