REST API version REST API URIs may specify a version number, such as /api/now/v1/table/(tablename) or no version number, such as /api/now/table/(tableName). URIs with a version number provide a consistent interface that is guaranteed to maintain backwards compatibility in future ServiceNow releases. For example, if the default response format for a particular HTTP method changes in a release, versioned URIs continue to use the previous format. By specifying a version number in your URIs, you can ensure that future updates to the REST API do not negatively impact your integration. URIs that do not specify a version number use the most recent REST API behavior available with your instance version, which may change when you upgrade.