Release notes contain information about new and deprecated features, breaking changes, and known issues. The following release notes apply for the most recent OpenShift Serverless releases on Red Hat OpenShift Service on AWS.

For an overview of OpenShift Serverless functionality, see About OpenShift Serverless.

OpenShift Serverless is based on the open source Knative project.

For details about the latest Knative component releases, see the Knative blog.

About API versions

API versions are an important measure of the development status of certain features and custom resources in OpenShift Serverless. Creating resources on your cluster that do not use the correct API version can cause issues in your deployment.

The OpenShift Serverless Operator automatically upgrades older resources that use deprecated versions of APIs to use the latest version. For example, if you have created resources on your cluster that use older versions of the ApiServerSource API, such as v1beta1, the OpenShift Serverless Operator automatically updates these resources to use the v1 version of the API when this is available and the v1beta1 version is deprecated.

After they have been deprecated, older versions of APIs might be removed in any upcoming release. Using deprecated versions of APIs does not cause resources to fail. However, if you try to use a version of an API that has been removed, it will cause resources to fail. Ensure that your manifests are updated to use the latest version to avoid issues.

Generally Available and Technology Preview features

Features which are Generally Available (GA) are fully supported and are suitable for production use. Technology Preview (TP) features are experimental features and are not intended for production use. See the Technology Preview scope of support on the Red Hat Customer Portal for more information about TP features.

The following table provides information about which OpenShift Serverless features are GA and which are TP:

Table 1. Generally Available and Technology Preview features tracker
Feature 1.23

kn func


kn func invoke


Service Mesh mTLS


emptyDir volumes


HTTPS redirection


Kafka broker


Kafka sink


Init containers support for Knative services


PVC support for Knative services


Deprecated and removed features

Some features that were Generally Available (GA) or a Technology Preview (TP) in previous releases have been deprecated or removed. Deprecated functionality is still included in OpenShift Serverless and continues to be supported; however, it will be removed in a future release of this product and is not recommended for new deployments.

For the most recent list of major functionality deprecated and removed within OpenShift Serverless, refer to the following table:

Table 2. Deprecated and removed features tracker
Feature 1.23

KafkaBinding API


kn func emit (kn func invoke in 1.21+)


Release notes for Red Hat OpenShift Serverless 1.23.0

OpenShift Serverless 1.23.0 is now available. New features, changes, and known issues that pertain to OpenShift Serverless on Red Hat OpenShift Service on AWS are included in this topic.

New features

  • OpenShift Serverless now uses Knative Serving 1.2.

  • OpenShift Serverless now uses Knative Eventing 1.2.

  • OpenShift Serverless now uses Kourier 1.2.

  • OpenShift Serverless now uses Knative kn CLI 1.2.

  • OpenShift Serverless now uses Knative Kafka 1.2.

  • The kn func CLI plug-in now uses func 0.24.

  • It is now possible to use the kafka.eventing.knative.dev/external.topic annotation with the Kafka broker. This annotation makes it possible to use an existing externally managed topic instead of the broker creating its own internal topic.

  • The kafka-ch-controller and kafka-webhook Kafka components no longer exist. These components have been replaced by the kafka-webhook-eventing component.

  • The OpenShift Serverless Functions Technology Preview now uses Source-to-Image (S2I) by default to build container images.

Known issues

  • The Federal Information Processing Standards (FIPS) mode is disabled for Kafka broker, Kafka source, and Kafka sink.

  • If you delete a namespace that includes a Kafka broker, the namespace finalizer may fail to be removed if the broker’s auth.secret.ref.name secret is deleted before the broker.

  • Running OpenShift Serverless with a large number of Knative services can cause Knative activator pods to run close to their default memory limits of 600MB. These pods might be restarted if memory consumption reaches this limit. Requests and limits for the activator deployment can be configured by modifying the KnativeServing custom resource:

    apiVersion: operator.knative.dev/v1alpha1
    kind: KnativeServing
      name: knative-serving
      namespace: knative-serving
      - name: activator
        - container: activator
            cpu: 300m
            memory: 60Mi
            cpu: 1000m
            memory: 1000Mi
  • If you are using Cloud Native Buildpacks as the local build strategy for a function, kn func is unable to automatically start podman or use an SSH tunnel to a remote daemon. The workaround for these issues is to have a Docker or podman daemon already running on the local development computer before deploying a function.

  • On-cluster function builds currently fail for Quarkus and Golang runtimes. They work correctly for Node, Typescript, Python, and Springboot runtimes.