# Envoy

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This page was generated from content adapted from the [AWS Developer Guide](https://github.com/awsdocs/aws-app-mesh-user-guide.git)
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## Envoy configuration variables

* **Note**\
  App Mesh Envoy 1.17 doesn't supports Envoy’s **v2 xDS** API. If you're using [Envoy configuration variables](https://docs.aws.amazon.com/app-mesh/latest/userguide/envoy-config.html) that accept Envoy config files, they must be updated to the latest\*\* v3 xDS\*\* API.

## Envoy defaults set by App Mesh

* **Note**\
  No matter if your Envoys have the Envoy or App Mesh default circuit breaker values, you cannot modify the values.