with the contact editor shipped with the sony xperia m and davdroid, the following vcard gets uploaded to a calypso server:
BEGIN:VCARD VERSION:3.0 UID:14d8467d-1404-4c7f-b78b-d61cb4e31ac0 FN:Test3 Suffix Only PRODID:DAVdroid/0.7.1 (ez-vcard/0.9.6) REV:20150318T161127Z END:VCARD
admittedly, the vcard was created by only filling the phonetic suffix name, but that’s likely to be a user error, and causes the server to reject it on grounds of violating the requirements of RFC 2426 (3.1.2 “N Type Definition”: The property MUST be present in the vCard object.).
please consider adding an empty N line in such cases (“N:;;;;” if i’m counting correctly) or storing contacts as vcard 4.0 (RFC 6350), where the N is optional.