Reference: Fataawa Ramadhaan – Volume 2, Page 555, Fatwa No.538
Fataawa as-Siyaam libni Jibreen – Page 60
Question: What is required from the one who delays making up the fasts of one Ramadhaan until the arrival of the following Ramadhaan?
Response: If this was done for a valid reason, for example, he was ill in bed for eleven months and was unable to fast that which was required of him, then all he has to do is [once again] make up the days missed. However, if he was negligent and was able to fast [but didn’t] then he has to feed a number of poor people for every day that he didn’t make up as expiation for his negligence.