# istio_48051.yaml
apiVersion: release-notes/v2
kind: feature
area: telemetry
issue:
  - 48051
releaseNotes:
  - |
    **Added** introduce `statsCompression` option in proxyConfig to allow global configuration of HTTP compression for the Envoy stats endpoint exposing its metrics. This is enabled by default, offering `brotli`, `gzip` and `zstd` depending on the `Accept-Header` sent by the client.
    **Deprecated** remove the `sidecar.istio.io/statsCompression` annotation, which is replaced by the `statsCompression` proxyConfig option. Per Pod overrides are still possible via `proxy.istio.io/config` annotation.

upgradeNotes:
  - title: HTTP compression of Envoy metrics (`prometheus_stats`) enabled by default.
    content: |
        The annotation `sidecar.istio.io/statsCompression` was deprecated and removed.

        There now is the `statsCompression` option in proxyConfig to globally control compression support of the metrics endpoint (`prometheus_stats`) of Envoy.
        The default of this value is `true`, offering `brotli`, `gzip` and `zstd` depending on the `Accept-Header` sent by the client.

        Most metric scrapers allow individual configuration of compression. If you still need to override this per Pod, you can set `statsCompression: false` via the `proxy.istio.io/config` annotation.