CONVERSION DURATION THRESHOLDplaceholder was deprecated on April 28th, 2014. Starting July 21st, 2014, using this placeholder with the
FeedMappingServicewill result in a
FeedMappingError.INVALID_PLACEHOLDER_FIELDerror for all AdWords API versions.
See this post for details on how to set your conversion duration going forward with the
CONVERSION TYPE IDplaceholder instead.
If you have any questions about this upcoming change or anything else related to the AdWords API, please contact us on the AdWords API forum or via the Google Ads Developers Google+ page.