A new version is released when backward-incompatible changes are made to the API. The current version is v1.
To ensure you always know about upcoming API changes, follow the Changelog.
You must specify a version in the URL with every request. By making your integration version aware, you anchor your code to specific features guaranteed to behave similarly for the supported timeframe.
Calling an API version
Rich Returns' API versions are explicitly declared in the URL that your integration calls:
/{ version }/{ endpoint }
For example, the following URLs call version v1:
/v1/returns