anchor.diff:                              <contextValue>20</contextValue>
                               <metadata>
                                   <contextMetadata>
  -                                    <name>attributeValueIdentifier</name>
  +                                    <name>ID</name>
                                       <type>long</type>
                                       <value>1</value>
                                   </contextMetadata>
  
positive.code: HOST: http://polls.apiblueprint.org/
  
  # IoT Broker NGSI data Interface
  
  (this document is work in progress and not yet finalized)
  
  The information exchange between the IoT Broker and other components is
  based on the FIWARE NGSI standards. Therefore, for readers familiar with
  FIWARE NGSI, this manual does not contain a lot of new information.
  
  # FIWARE NGSI data model
  
  
negative.code: updateContextRequest; the response body is an instance of 
  updateContextResponse. 
  
  ### Update context data [POST]
  
  + Request (application/xml)
  
  