Changes may be made to the API to correct errors or to introduce new functionality. When changed, a new version of the API will be made available via a new URL. Merchant should always use the latest version of the API.
The general rule is that old versions of the API will be discontinued two years after the release of the successor. But if deemed necessary, for example for security reasons, a version of the API may be discontinued prematurely. As new functionality is introduced to the system the behavior of an existing version of the API may change, e.g. existing faults may also be used in new situations.