All perfect praise be to Allaah, the Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.
The Muslim who delayed making up for a Ramadan or some of its days without a valid excuse until the next Ramadan has to make an expiation, which is to feed one needy person for each day that he delayed. This is the opinion of the Maaliki, Shaafi‘i and Hanbali scholars. We consider it the preponderant opinion because Abu Hurayrah and Ibn ‘Abbaas gave a Fatwa (verdict) to that effect and the Companions were not reported to have contested it either.
It is permissible for the Muslim, who is required to make expiation, to offer it before making up for the days. We do not know any scholar who considers this expiation obligatory prohibiting offering the expiation before making up for the days of fasting. Combining between them is, in principle, not a condition. So, whenever he makes the expiation, he will be free from liability. Some scholars have held that it is recommended to make expiation with fasting or after it.
And Allaah Knows best.