The Messenger of Allah ﷺ stayed in Mecca for fifteen nights during the year of the Conquest, shortening the prayer.
حدثنا أبو يوسف الصيدلاني محمد بن أحمد الرقي حدثنا محمد بن سلمة عن محمد بن إسحق عن الزهري عن عبيد الله بن عبد الله بن عتبة
أن رسول الله ﷺ أقام بمكة عام الفتح خمس عشرة ليلة يقصر الصلاة
Graded sahih, and reported by Abu Dawud in the chapter on the prayer of travel, section titled "When does the traveler complete his prayer?", number 1231, from the hadith of Muhammad bin Salama, through this same chain. It has a strong corroborating narration in Nasai, and by this the hadith is confirmed as sahih.