// Module included in the following assemblies:
// * service_mesh/v2x/upgrading-ossm.adoc

:_mod-docs-content-type: CONCEPT
[id="ossm-upgrade-24-25-changes_{context}"]
= Upgrade changes from version 2.4 to version 2.5

== Istio OpenShift Routing (IOR) default setting change

The default setting for Istio OpenShift Routing (IOR) has changed. The setting is now disabled by default.

You can use IOR by setting the `enabled` field to `true` in the `spec.gateways.openshiftRoute` specification of the `ServiceMeshControlPlane` resource.

[source,yaml]
----
apiVersion: maistra.io/v2
kind: ServiceMeshControlPlane
spec:
  gateways:
    openshiftRoute:
      enabled: true
----

== Istio proxy concurrency configuration enhancement

For consistency across deployments, Istio now configures the `concurrency` parameter based on the CPU limit allocated to the proxy container. For example, a limit of 2500m would set the `concurrency` parameter to 3. If you set the `concurrency` parameter to a value, Istio uses that value to configure how many threads the proxy runs instead of using the CPU limit. 

Previously, the default setting for the parameter was 2. 
