Did Abu Bakr add "Allahu Akbar" at the end of the Athan?

Allah has perfected and completed the religion, and no one is permitted to add to it or subtract from it. There is no authenticated knowledge regarding what was narrated from Abu Bakr concerning the Adhan. The Adhan was a true vision seen by Abdullah bin Zayd and confirmed by the Prophet (peace and blessings of Allah be upon him). Abu Bakr is not mentioned in the narrations concerning the legitimacy of the Adhan. Indeed, Ahmad, Abu Dawud, and others narrated from Abdullah bin Zayd bin Abd Rabbo the details of his vision, and how the Adhan and Iqama were performed. They also narrated that the Prophet (peace and blessings of Allah be upon him) affirmed it and commanded that the Adhan be called in that manner, and Bilal used to call the Adhan accordingly.