PROPFIND /dav/addressbook/ HTTP/1.1
Brief: t
Content-Type: text/xml
Depth: 0
Prefer: return=minimal

<?xml version="1.0" encoding="UTF-8"?>
<A:propfind xmlns:A="DAV:">
  <A:prop>
    <D:getctag xmlns:D="http://calendarserver.org/ns/"/>
    <A:sync-token/>
  </A:prop>
</A:propfind>