<?xml version="1.0" encoding="utf-8" ?>
<c:calendar-query xmlns:d="DAV:" xmlns:c="urn:ietf:params:xml:ns:caldav">
    <d:prop>
        <d:getetag />
    </d:prop>
    <c:filter>
        <c:comp-filter name="VCALENDAR">
            <c:comp-filter name="VEVENT" />
        </c:comp-filter>
    </c:filter>
</c:calendar-query>