Syedna Qutbuddin has stated that Syedna Burhanuddin proclaimed Nass on him in private 50 years ago right before he publicly declared his appointment as Mazoon. Syedna Burhanuddin also said at that time that it will become known in the future (jiware zahir thaase tiwaare thaase).
Nass in private from the Dai to his Mansoos without any other witnesses is valid. Syedna Taher Saifuddin explains in his risalat 1363H (p.144), on the authority of Syedi Ameenji b. Jalaal and Syedna Daud b. Qutubshah, the private Nass performed by the 7th Dai Syedna Ahmad bin Mubarak on 8th Dai Syedna Husain bin Ali. After Syedna Ahmad’s wafat, his successor the Syedna Husain himself declared that he had been appointed by his predecessor in private without any witnesses, for reasons pertaining to the welfare of Dawat. Syedna Husain also asserted that there was no one at par with him in ‘ilm and knowledge. He presented a book of haqiqat he had written (kitab al-Īḍāḥ wa l-Bayān) and challenged anyone to produce anything similar. The excerpt relating to this account with translation is in the documentary evidence section below.
Syedna Qutbuddin’s ‘ilm and knowledge of Fatimid theology is unparalleled and has been attested to by statements by Syedna Taher Saifuddin and Syedna Mohammed Burhanuddin.