.. _faq_api_v3_config: How do I configure Envoy to use the v3 API? =========================================== All bootstrap files are expected to be v3. For dynamic configuration, we have introduced two new fields to :ref:`config sources `, transport API version and resource API version. The distinction is as follows: * The :ref:`transport API version ` indicates the API endpoint and version of *DiscoveryRequest*/*DiscoveryResponse* messages used. * The :ref:`resource API version ` indicates whether a v2 or v3 resource, e.g. v2 *RouteConfiguration* or v3 *RouteConfiguration*, is delivered. The API version must be set for both transport and resource API versions. If you see a warning or error with ``V2 (and AUTO) xDS transport protocol versions are deprecated``, it is likely that you are missing explicit V3 configuration of the transport API version.