There isn't any[1] info in the documentation about which Gateway API CRD's should be installed with which OSSM version when the user wants to use Gateway API experimental feature.

The backward compatibility is not guaranteed for Gateway API CRDs (since the Gateway API CRDs were in an experimental phase) so each OSSM version should use the specific Gateway API CRDs version (according to the Istio version).

Some table will be helpful in this case:

How to install CRD's:
Standard

kubectl get crd gateways.gateway.networking.k8s.io || { kubectl kustomize "github.com/kubernetes-sigs/gateway-api/config/crd?ref=v0.5.1" | kubectl apply -f -; }

Experimental

kubectl get crd gateways.gateway.networking.k8s.io || { kubectl kustomize "github.com/kubernetes-sigs/gateway-api/config/crd/experimental?ref=v0.5.1" | kubectl apply -f -; }

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[1] - For OSSM 2.3.9 , there is info how to install CRD's https://docs.openshift.com/container-platform/4.14/service_mesh/v2x/servicemesh-release-notes.html#installing-the-gateway-api-crds with version `v0.4.0`

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[2] - ref:
istio 1.14: https://istio.io/v1.14/docs/tasks/traffic-management/ingress/gateway-api/
istio 1.16: https://istio.io/v1.16/docs/tasks/traffic-management/ingress/gateway-api/
istio 1.18: https://istio.io/v1.18/docs/tasks/traffic-management/ingress/gateway-api/