The Messenger of Allah ﷺ said, "There is no zakat due on a slave except zakat al-fitr."
عن رسول الله ﷺ قال: ليس في العبد صدقة إلا صدقة الفطر.
Muslim narrated it (10/982) through several routes from Ibn Wahb, who said, Makhrama told me, from his father, from Arak bin Malik, who said, "I heard Abu Hurairah narrating from the Messenger of Allah ﷺ," and he went on to relate the hadith. See further references in the combined chapters on the zakat of livestock.As for what was narrated from Abdullah bin Amr bin As, that the Prophet ﷺ sent a caller through the pathways of Makkah announcing, "The charity of Fitr is obligatory upon every Muslim, male or female, free or slave, young or old, two mudd of wheat, or a saa of any other food," this is daif. Tirmidhi narrated it (674) from Uqba bin Mukram, who said, Salim bin Nuh told us, from Ibn Jurayj, from Amr bin Shuayb, from his father, from his grandfather, and he related it.Tirmidhi said, "This is a hasan gharib hadith. Umar bin Harun narrated this hadith from Ibn Jurayj, and said, from Abbas bin Mina, from the Prophet ﷺ, and he mentioned part of this hadith. Jarud told us, Umar bin Harun told us, this hadith."I say, Umar bin Harun is discarded, and Salim bin Nuh is disputed, Ibn Main, Nasai, Daraqutni and others graded him daif, and he is among the narrators used by Muslim. As for Abbas bin Mina, if he is Abbas bin Abdul-Rahman bin Mina Ashjai, then he belongs to the junior generation of the Tabiin.Likewise, what was narrated from Anas bin Malik as a raised report is not sahih, "The fasting of a servant remains suspended between heaven and earth until Zakat al-Fitr is paid." Ibn Jawzi narrated it in Ilal Mutanahiya (823) through the route of Khatib Baghdadi, and it is also in his history (121/9), from Muhammad bin Talha Naali, who said, Abu Salih Sahl bin Ismail bin Sahl Jawhari Tarsusi told us, who said, Abu Abbas Muhammad bin Hasan bin Qutayba Asqalani told us, who said, Muhammad bin Abu Sari Asqalani told us, who said, Baqiyya told us, Abdul-Rahman bin Uthman told me, from Anas bin Malik, and he related it.Ibn Jawzi said, "In it is Abdul-Rahman bin Uthman. Ahmad said, 'People discarded his hadith,' and Ibn Hibban said, 'It is not permissible to rely on him as evidence.'" End of quote.I add here what Ibn Hibban said in Majruhin (599), "He is Abu Bahr Bakrawi, from the people of Basra. He narrates from Shuba. He died in the year one hundred and ninety-five. His hadith is rejected. He is among those who narrate inverted reports from reliable narrators, and he brings from trustworthy narrators things that do not resemble their hadiths."Since this Bakrawi died in the year 195 AH, and Anas died in the year 92 or 93 AH, he could not have met him, given how much later his death was. So there is also a gap in the chain of transmission. It is therefore either disconnected, or daif because of this Abdul-Rahman bin Uthman, and if he is someone other than the one mentioned before, then he is unknown.Likewise, what was narrated from Jareer as a raised report is not sahih, with the wording, "The month of Ramadan remains suspended between heaven and earth, and it is not raised up except by Zakat al-Fitr." Ibn Jawzi narrated it in Ilal Mutanahiya (824) and said about it, "Muhammad bin Ubayd is unknown." Hafiz added in Lisan (276/5), saying, "He has no corroborating narrator."