1985 كان فيما أنزل من القرآن: (عشر رضعات معلومات يحرمن)، ثم نسخن، بخمس معلومات، فتوفي رسول الله صلى الله عليه وسلم وهن فيما يقرأ من القرآن
It was revealed in the Qur'an that: ten times of breastfeeding known with certainty establish prohibition (Mahram relationship through breastfeeding); then that was abrogated and replaced with five times of breastfeeding known with certainty. The Messenger of Allah (may Allah's peace and blessings be upon him) died while these (words of the abrogating verse) were still being recited as part of the Qur'an

عن عائشة، أنها قالت: "كان فِيمَا أُنْزِلُ من القرآن: (عَشْرُ رَضَعَاتٍ مَعْلُومَاتٍ يُحَرِّمْنَ)، ثم نُسِخْنَ بِخَمْسٍ مَعْلُومَاتٍ، فَتُوُفِّيَ رَسُولُ الله صلى الله عليه وسلم ، وهُنَّ فِيمَا يُقْرَأُ من القرآن".

‘Ā'ishah (may Allah be pleased with her) reported: It was revealed in the Qur'an that: ten times of breastfeeding known with certainty establish prohibition (Mahram relationship through breastfeeding); then that was abrogated and replaced with five times of breastfeeding known with certainty. The Messenger of Allah (may Allah's peace and blessings be upon him) died while these (words of the abrogating verse) were still being recited as part of the Qur'an.

صحيح - ( رواه مسلم ). Sahih/Authentic. [Muslim]

في هذا الحديث بيان أنَّ الرضاع المحرِّم كان في أول الأمر عشر رضعات نزل بها القرآن، فنسخ لفظه وحُكمه، إلى خمس رضعات يحرمن، وتوفي رسول الله صلى الله عليه وسلم وهنَّ مما يقرأ، لتَأَخَّرَ إِنْزالُ الناسخ جدًّاً، حتى خفي على بعض الناس، وكان يقرأ الآية المنسوخة على انها من القرآن.
According to this Hadīth, the Qur’an initially stated that ten times of confirmed breastfeeding make the breastfed person Mahram (unmarriageable) to those who shared breastfeeding from the same woman and their Mahram relatives. Yet, both the ruling and wording of this verse were abrogated and replaced with another verse stipulating five times of confirmed breastfeeding. Later, only the wording of the latter verse was abrogated while its ruling remained in force. As for ‘Ā'ishah's statement that the Prophet died while this verse was still being recited as part of the Qur'an, it means that the abrogation came so late that news of it did not reach some people and, thus, they continued reciting the abrogated verse as part of the Qur’an due to their ignorance of its abrogation.

أن الرضاع الذي تثبت به الحرمة خمس رضعات، وما نقص عنها فلا يُحرِّم. إثبات علو الله تعالى؛ لأن النزول لا يكون إلا من أعلى. أنه لا يجوز العمل بالمنسوخ. خفاء النسخ على بعض الصحابة، وهذا لا يؤثر في حفظ القرآن الكريم.