During the era of Hazrat Abu Bakr (ra), the compilation of the Holy Quran [into book form] was initiated. A committee consisting of [several] companions was formed for this task of which Hazrat Ubayy (ra) was its supervisor. Hazrat Ubayy (ra) would recite the Holy Quran and the companions would write it down. Since this committee comprised of those who were very learned and possessed deep knowledge, occasionally they would have discussion and discourse on certain verses. When the following verse of Surah al-Taubah was being written down:
ثُمَّ انْصَرَفُوْا صَرَفَ اللّٰهُ قُلُوْبَهُمْ بِاَنَّهُمْ قَوْمٌ لَّا يَفْقَهُوْنَ
[Then they turn away. Allah has turned away their hearts because they are a people who would not understand. (Ch.9: V.127)]
It was mentioned that this was the final verse to be revealed. Hazrat Ubayy (ra) stated that in fact there were two more verses that the Holy Prophet (sa) taught him after this. Therefore, this was not the last verse, rather there were two verses revealed after that as well.
(Sheikh Shah Moinuddin Ahmad Nadvi, Siyar al-Sahabah, Vol. 3 [Karachi, Pakistan: Dar al-Ishaah Urdu Bazar, 2004] 142)