It wasnarrated that Abu Sa'eed said:
"The Messenger of Allah (ﷺ)said: 'Whoever sleeps and misses Witr, or forgets it, let him prayitwhen morning comes, or when he remembers.'" (FR)
English reference (FR): Vol. 1, Book 5, Hadith 1188 (FR)
Arabic reference (FR): Book 5, Hadith 1244 (FR)