# istio_http2-probes.yaml
apiVersion: release-notes/v2
kind: feature
area: traffic-management
issues:
- 40173
releaseNotes:
- |
  **Added** support for ALPN negotiation to Istio [health checks](https://istio.io/latest/docs/ops/configuration/mesh/app-health-check/), mirroring
  how Kubelet functions. This allows `HTTPS` type probes to use HTTP2. To revert to the old behavior, which always used HTTP/1.1, the `ISTIO_ENABLE_HTTP2_PROBING=false` variable can be set.