Update upgradefailed-error.md

Edit review per CI 7006

Author: przlplx

support/azure/azure-kubernetes/error-codes/upgradefailed-error.md

@@ -1,124 +1,79 @@
 ---
-title: Troubleshoot the UpgradeFailed error code
-description: Learn how to troubleshoot the UpgradeFailed error code when you attempt to upgrade an AKS cluster using the Azure CLI.
+title: Troubleshoot the UpgradeFailed Error
+description: Learn how to troubleshoot the UpgradeFailed error when you try to upgrade an AKS cluster by using the Azure CLI.
 ms.date: 08/05/2025
 editor: v-jsitser
 ms.reviewer: v-liuamson
 ms.service: azure-kubernetes-service
-#Customer intent: As an Azure Kubernetes user, I want to troubleshoot the UpgradeFailed - AKS upgrade failed due to unsupported Kubernetes version or node pool version skew error code so that I can successfully upgrade an AKS cluster using the Azure CLI.
+#Customer intent: As an Azure Kubernetes user, I want to troubleshoot the "AKS upgrade failed due to unsupported Kubernetes version or node pool version skew" error so that I can successfully upgrade an AKS cluster by using the Azure CLI.
 ms.custom: sap:Create, Upgrade, Scale and Delete operations (cluster or nodepool)
 ---
-# Error code: UpgradeFailed - AKS upgrade failed due to unsupported Kubernetes version or node pool version skew
+# Troubleshoot a failed AKS cluster upgrade
 
 ## Prerequisites
 
-This article requires Azure CLI version 2.67.0 or a later version. \
-To find the version number, run az \--version. If you have to install or
-upgrade Azure CLI, see [How to install the Azure
-CLI](/cli/azure/install-azure-cli).
+This article requires Azure CLI version 2.67.0 or a later version. To find the version number, run `az \--version`. If you have to install or upgrade Azure CLI, see [How to install the Azure CLI](/cli/azure/install-azure-cli).
 
-For more detailed information about the upgrade process, see the
-\"Upgrade an AKS cluster\" section in [Upgrade an Azure Kubernetes
-Service (AKS)
-cluster](/azure/aks/upgrade-cluster#upgrade-an-aks-cluster).
+For more detailed information about the upgrade process, see the \"Upgrade an AKS cluster\" section in [Upgrade an Azure Kubernetes Service (AKS) cluster](/azure/aks/upgrade-cluster#upgrade-an-aks-cluster).
 
 ## Symptoms
 
-When attempting to upgrade an AKS cluster using the Azure CLI, the
-upgrade operation fails with one or more of the following errors:
+When you try to upgrade an AKS cluster by using the Azure CLI, the upgrade operation fails and returns one or more of the following error messages:
 
-**(K8sVersionNotSupported)** Managed cluster `ClusterName` is on
-version 1.25.6 which is not supported in this region.
-
-Or  \
- \
-**(OperationNotAllowed)** Upgrading Kubernetes version 1.24.9 to 1.26.6
-is not allowed.
-
-Or
-
-**(NodePoolMcVersionIncompatible)** Node pool version 1.24.9 and control
-plane version 1.29.15 are incompatible.
+> **(K8sVersionNotSupported)** Managed cluster `ClusterName` is on version 1.25.6 which is not supported in this region.
+>
+> **(OperationNotAllowed)** Upgrading Kubernetes version 1.24.9 to 1.26.6 is not allowed.
+>
+> **(NodePoolMcVersionIncompatible)** Node pool version 1.24.9 and control plane version 1.29.15 are incompatible.
 
 ## Cause
 
-The upgrade failures are due to one or more of the following reasons:
-
-- The target Kubernetes version (e.g., 1.25 or 1.26) is no longer
-  supported in the selected Azure region.
-
-- Skipping minor versions during upgrades (e.g., from 1.24.x to 1.26.x
-  or 1.27.x) is not allowed unless the current version is unsupported.
+The upgrade failures occur for one or more of the following reasons:
 
-- A control plane and node pool version skew occurred when attempting
-  to upgrade only the control plane, causing the following version skew
-  error:
+- The target Kubernetes version (for example, 1.26 or 1.25) is no longer supported in the selected Azure region.
 
-- Node pool version is more than 3 minor versions behind the control
-  plane.
+- A minor version is skipped. Skipping minor versions during upgrades (for example, from 1.24.*x* to 1.26.*x* or 1.27.*x*) is not allowed unless the current version is unsupported.
 
-To understand more about these errors, you may check the following
-articles:
+- A control plane and node pool version skew occurs when you try to upgrade only the control plane. This condition causes the following version skew  error:
 
-- AKS supported Kubernetes versions:
-  <https://aka.ms/aks-supported-k8s-ver>.
+- The node pool version is more than three minor versions behind the control plane.
 
-- AKS upgrade version skew policy:
-  <https://aka.ms/aks/UpgradeVersionRules>.
+To understand more about these errors, see [AKS supported Kubernetes versions](https://aka.ms/aks-supported-k8s-ver) and [AKS upgrade version skew policy](https://aka.ms/aks/UpgradeVersionRules).
 
-## Solution
+## Resolution
 
-### Step 1: Confirm the current version and available upgrade paths
+To resolve this issue, follow these steps.
+ 
+**Step 1:** Verify the current version and available upgrade paths. To view the current Kubernetes version and supported upgrade targets, run the following command:
 
-Run the following command to view the current Kubernetes version and
-supported upgrade targets:
+> az aks get-upgrades \--resource-group \<RG\> \--name \<ClusterName\> \--output table
 
-**az aks get-upgrades \--resource-group \<RG\> \--name \<ClusterName\>
-\--output table**
+If only newer versions, such as 1.29.*x*, are listed, and intermediate versions, such as 1.27.*x*, 1.26.*x*, or 1.25.*x*, are missing, the missing versions are deprecated in your region.
 
-If only newer versions such as 1.29.x are listed, and intermediate
-versions like 1.25.x, 1.26.x, or 1.27.x are missing, this indicates that
-those versions are deprecated in your region.
+**Step 2:** Try to run a full upgrade (control plane and node pool together). Because of the version skew policy (control planes can't be more than three minor versions ahead of node pools), a separate control plane-only upgrade might fail. Instead, upgrade both the control plane and node pool together:
 
-### Step 2: Attempt full upgrade (control plane and node pool together)
+> az aks upgrade \--resource-group \<RG\> \--name \<ClusterName\> \--kubernetes-version \<available upgrade version\> \--yes
 
-Due to the version skew policy (control planes cannot be more than 3
-minor versions ahead of node pools), a separate control-plane-only
-upgrade may fail. Instead, upgrade both the control plane and node pool
-together: \
- \
-**az aks upgrade \--resource-group \<RG\> \--name \<ClusterName\>
-\--kubernetes-version \<available upgrade version\> \--yes**
+This action ensures compliance with the version skew policy by coordinating a supported Kubernetes version and an upgrade of both components.
 
-This will ensure compliance with the version skew policy, use of a
-supported Kubernetes version and upgrade of both components in a
-coordinated manner
+## More information
 
-## Additional Tips
+- Always verify the supported versions in your region by running the following command:
 
-- Always validate supported versions in your region using: \
-    az aks get-versions \--location \<region\> \--output table
+   > az aks get-versions \--location \<region\> \--output table
 
-- Avoid attempting to upgrade to deprecated versions. AKS may enforce
-  immediate skips to supported long-term versions (e.g., 1.29)
+- Avoid trying to upgrade to deprecated versions. AKS might enforce immediate skips of supported long-term versions (for example, 1.29).
 
-- For AKS clusters running significantly outdated Kubernetes versions,
-  the recommended best practices include:  
+- For AKS clusters that are running significantly outdated Kubernetes versions, the recommended best practices include:  
 
-**Create a New Cluster:** Spin up a new AKS cluster with a supported
-Kubernetes version.  
+   **Create a new cluster:** Create an AKS cluster that has a supported Kubernetes version.  
 
-**Migrate Workloads:** Transfer your workloads to the new cluster to
-ensure they run on supported versions.  
+   **Migrate workloads:** Transfer your workloads to the new cluster to make sure that they run on supported versions.  
 
-**Avoid Upgrading Across Multiple Versions:** Instead of upgrading
-through several minor versions, moving to a new cluster minimizes
-complexity and potential issues.  
+   **Avoid upgrading across multiple versions:** Instead of upgrading through several minor versions, move to a new cluster to minimize complexity and potential issues.  
 
-**Backup and Validate Data:** Ensure all data is backed up and validated
-before migration.  
+   **Back up and verify data:** Make sure that all data is backed up and verified before the migration.  
 
-**Test Thoroughly:** Perform thorough testing in a staging environment
-to identify and resolve any compatibility issues.  
+   **Test thoroughly:** Perform thorough testing in a staging environment to identify and resolve any compatibility issues.  
 
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