Jami` at-Tirmidhi 674
جامع الترمذي#674Da'ifAmr bin Shu'aib narrated from his grandfather that :the Prophet sent a caller in the roads of Makkah proclaiming "Sadaqatul-Fitr is required upon every Muslim, male or female, free or slave, young or old; it is two Mudd of wheat or its equivalent of a Sa of food
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Ahmad Muhammad ShakirDaif Isnaad
Al-AlbaniDaif Isnaad
Zubair Ali ZaiDaif
In-book reference: 7:58