New IRCC (Immigration, Refugees and Citizenship Canada) guidance suggests certification is not the thing an officer checks first. Get a Free Consultation on Applying for Canadian Citizenship by DescentFive points from the presentation stand out for citizenship by descent applicants:These details come from a slide deck IRCC presented on Canadian citizenship by descent, to the ACA, together with the association's published summary of the question period that followed. For primary documents, IRCC says an applicant must provide one or more for each ancestor. It also published the names of those who lost Canadian citizenship, and of those who lost British subject status before 1947. Get a Free Consultation on Applying for Proof of Canadian Citizenship