MS Dynamics NAV: Updating data

[KDGundermann]

When updating an object in MS Dynamics NAV you will receive an error message:
<m:message xml:lang="en-US">
Could not validate the client concurrency token required by the service. Please provide a valid token in the client request.
</m:message>

For every GET request the NAV server delivers an ETag:

• one ETag in the HTML-Header
• one ETag as an attribute in the XML node
  <entry m:etag="W/&quot;'28%3BEgAAAAJ7BTEAMAAwADAAMAAAAAAA8%3B826339620%3B'&quot;">
• another ETag as an Entity in the XML/JSON document

When updating an object, you have to deliver this ETag as an "If-Match" option in the HTML Header