def METHOD_NAME(zone, server):
    """
    Checks a zone's serial on a server.
    :return: serial if received; None if the server did not know; False on error
    """
    query = dns.message.make_query(zone, "SOA")
    try:
        response = dns.query.tcp(query, server, timeout=5)
    except dns.exception.Timeout:
        return False
    for rrset in response.answer:
        if rrset.rdtype == dns.rdatatype.SOA:
            return int(rrset[0].serial)
    return None