It's coming up to two years since getting my Green Card, and I'm just filing my I-751 to remove the conditions. Think I have most of it in order, but stumbled over one of the 'Evidence of Relationship' documents. It asks for an Affidavit "...sworn to or affirmed by at least two people" from someone we've known since conditional residence was granted. My questions are 1) is this compulsory? 2) if it is, does it need to be notarized? and 3) is it simply a letter stating the basic facts as laid out? Finally, it adds 'Affidavits must be supported by other types of evidence listed above'... what does this mean? The other evidence listed is things like joint statements and financial records - how can this relate to this third party affidavit? Hope my question wasn't too long, and thanks in advance for any information.