Sahih Muslim Book 6, Hadith Number 2467.

Chapter : Permissibility of observing the fast or not observing it in the month of Ramadan for a traveller.

This Hadith is narrated on the authority of Zuhri with the same chain of transmitters. Yahya (one of the narrators) said that Sufyan (the narrator) had stated: I do not know whose statement it is: “It is the last word of the Messenger of Allah (may peace be upon him) which is accepted as (final as it abrogates the previous ones).”