API Versioning

All Amazon SimpleDB API operations are versioned. This minimizes the impact of API changes on client software by sending back a response that the client can process. New versions are designed to be backward-compatible with older API revisions. However, there might be occasions where an incompatible API change is required. Additionally, newer API responses might include additional fields and, depending on how the client software is written, it might not be able to handle additional fields. Including a version in the request guarantees that it will always be sent a response that it expects.

Each API revision is assigned a version in date form. This version is included in the request as part of the document namespace when using SOAP and as a version parameter when using REST. The response returned by Amazon SimpleDB honors the version included in the request. Fields introduced in a later API version are not returned in the response.

If your SOAP client retrieves the Amazon SimpleDB WSDL at runtime and generates the requests using that WSDL dynamically, you must reference the WSDL of the API version on which you built the client. This ensures the client software continues to operate if incompatible API changes are introduced. The WSDL for each supported API version is available using the following URI format:

http://sdb.amazonaws.com/doc/<api-version>/AmazonSimpleDB.wsdl