Whoever prays at night should make the last of his prayers witr, for the Messenger of Allah ﷺ commanded this. Once dawn arrives, the time for all night prayers and witr has passed, for the Messenger of Allah ﷺ said, "Pray witr before dawn."
حدثنا عبد الرزاق وابن بكر قالا أخبرنا ابن جريج حدثني سليمان بن موسى حدثنا نافع أن
من صلى بالليل فليجعل آخر صلاته وترا فإن رسول الله ﷺ أمر بذلك فإذا كان الفجر فقد ذهبت كل صلاة الليل والوتر فإن رسول الله ﷺ قال أوتروا قبل الفجر
Its chain of transmission is sahih. The meaning of the marfu hadith has already appeared repeatedly through other routes, the most recent being 6300, and see also 6355. Its meaning will also come again right after this.