The category hierarchy for a given marketplace has a version level. To determine the category hierarchy version:

  1. The first time your application retrieves the categories for a particular marketplace, call GetCategories with the value of DetailLevel set to ReturnAll. This returns the category data and the version for that marketplace's category hierarchy. Store this value for future use.
  2. When the application next seeks to refresh the category data for that eBay marketplace, call GetCategories with no DetailLevel value specified. This causes GetCategories to return only the category hierarchy version.
  3. Compare this newly retrieved version number with the one retrieved in the last call:
    • If the newly retrieved version number is different, call GetCategories again but with the value of DetailLevel set to ReturnAll to retrieve the category data. Store the new version number as the reference point for the next call.
    • If the new and stored version numbers are the same, then category data does not need to be retrieved for that marketplace at that time.

Note: Changes to the category hierarchy of one marketplace are independent of changes made to another marketplace. The category hierarchy version must be independently checked for each eBay marketplace the application supports, using the procedure described above.

The eBay category hierarchy is updated on a monthly basis, but may be updated more frequently. It is a good idea to call GetCategories to check the category tree version at least once on each day that the application is being used.