Added release notes & documentation changes for Mx4PC 2.21.1.

Author: zlogic

content/en/docs/deployment/private-cloud/private-cloud-cluster/_index.md

@@ -194,13 +194,13 @@ kind: OperatorConfiguration
 # omitted lines for brevity
 # ...
 spec:
-  baseOSImageTagTemplate: 'ubi8-1-jre{{.JavaVersion}}-entrypoint'
+  baseOSImageTagTemplate: 'ubi9-1-jre{{.JavaVersion}}-entrypoint'
 ```
 
 At the moment, the `baseOSImageTagTemplate` can be set to one of the following values:
 
-* `ubi8-1-jre{{.JavaVersion}}-entrypoint` - to use Red Hat UBI 8 Micro images; this is the default option.
-* `ubi9-1-jre{{.JavaVersion}}-entrypoint` - to use Red Hat UBI 9 Micro images; this option can be used to use a newer OS and improve security scores.
+* `ubi8-1-jre{{.JavaVersion}}-entrypoint` - to use Red Hat UBI 8 Micro images; this option can be used for some cases where backward compatibility is needed.
+* `ubi9-1-jre{{.JavaVersion}}-entrypoint` - to use Red Hat UBI 9 Micro images; this is the default option.
 
 {{% alert color="info" %}}
 
@@ -964,6 +964,10 @@ In addition to internal Mendix Runtime paths, `/tmp` is mounted for any temporar
 If your app works without issues when read-only root filesystem is enabled, it is best to enable it wherever possible. We recommend using a non-production environment to validate that your app keeps working correctly with a read-only RootFS.
 {{% /alert %}}
 
+{{% alert color="warning" %}}
+Enabling the `runtimeReadOnlyRootFilesystem` option will cause the `model/resources` directory to be empty. If your app (or Marketplace modules such as SAML) uses the `model/resources` directory for resources such as configuration data and other resources, consider moving those resources to another location (such as `model/userlib`) or loading them from FileDocument entities.
+{{% /alert %}}
+
 ### GKE Autopilot Workarounds {#gke-autopilot-workarounds}
 
 In GKE Autopilot, one of the key features is its ability to automatically adjust resource settings based on the observed resource utilization of the containers. GKE Autopilot verifies the resource allocations and limits for all containers, and makes adjustments to deployments when the resources are not as per its requirements.

content/en/docs/releasenotes/deployment/mendix-for-private-cloud.md

@@ -12,6 +12,15 @@ For information on the current status of deployment to Mendix for Private Cloud
 
 ## 2025
 
+### March ???, 2025
+
+#### Mendix Operator v2.21.1 {#2.21.1}
+
+* We have updated components to use the latest dependency versions in order to improve security score ratings for container images.
+* For new installations, the Operator will now use ubi9 as the base image for Mendix apps. Existing installations will keep their configuration and stay on ubi8. For more information on base image versions, see the [Runtime Base Image](/developerportal/deploy/private-cloud-cluster/#runtime-base-image) section.
+* We've fixed a regression that caused the `model/resources` directory to appear empty, and caused problems with some Marketplace modules such as SAML (Ticket 242648).
+* Upgrading to Mendix Operator v2.21.0 from a previous version will restart environments managed by that version of the Operator. Environments with 2 or more replicas and a **PreferRolling** update strategy will be restarted without downtime.
+
 ### March 6, 2025
 
 #### Portal Improvements
@@ -40,6 +49,12 @@ For information on the current status of deployment to Mendix for Private Cloud
 
 With the introduction of ephemeral storage requests and limits, building an app requires at least 2 GB of ephemeral storage available on the Kubernetes node. If your nodes do not have enough temporary storage, the build pods cannot start and their status remains **Pending**. To resolve this issue, you can lower the values for `ephemeral-storage` in the [buildResources](/developerportal/deploy/private-cloud-cluster/#resource-definition-ocm) configuration.
 
+#### Known Issue
+
+This issue has been fixed in Mendix Operator [version 2.21.1](#2.21.1).
+
+* The `model/resources` directory is empty when starting the app, causing issues with some Marketplace modules (such as SAML) that use that location to store configuration data and other resources.
+
 ### February 12, 2025
 
 #### Documentation Updates