Update aks-upgrade-blocked.md

Edit review per CI 7006

Author: przlplx

support/azure/azure-kubernetes/error-codes/aks-upgrade-blocked.md

@@ -1,111 +1,100 @@
 ---
-title: AKS upgrade not allowed or blocked due to unsupported Kubernetes version or node pool version skew
-description: Learn how to troubleshoot AKS upgrade not allowed or blocked due to unsupported Kubernetes version or node pool version skew.
+title: AKS upgrade not allowed or blocked because of unsupported Kubernetes version or node pool version skew
+description: Learn how to troubleshoot AKS upgrade not allowed or blocked because of unsupported Kubernetes version or node pool version skew.
 ms.date: 08/20/2025
 editor: v-jsitser
 ms.reviewer: v-liuamson
 ms.service: azure-kubernetes-service
-#Customer intent: As an Azure Kubernetes user, I want to troubleshoot AKS upgrade not allowed or blocked due to unsupported Kubernetes version or node pool version skew 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)
+#Customer intent: As an Azure Kubernetes user, I want to troubleshoot an AKS upgrade not allowed or blocked because of an unsupported Kubernetes version or node pool version skew 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 node pool)
 ---
-# AKS upgrade not allowed or blocked due to unsupported Kubernetes version or node pool version skew
+# Troubleshoot AKS upgrade errors because of version skew, incompatibility, or lack of support
 
 ## Prerequisites
 
-This article requires Azure CLI version 2.67.0 or a later version.
-To find the version number, run `az --version`. If you need 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 the 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 options and recommendations for Azure Kubernetes Service (AKS) clusters](/azure/aks/upgrade-cluster#upgrade-an-aks-cluster).
 
 ## Symptoms
 
-When attempting to upgrade an AKS cluster using the Azure CLI, the upgrade operation is blocked with one or more of the following errors:
+When you try to upgrade an AKS cluster by using the Azure CLI, the upgrade operation is blocked 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.
-Please use the `[azaks get-versions]` command to get the supported version list in this region.
-For more information, see [Supported Kubernetes versions in Azure Kubernetes Service (AKS)](https://aka.ms/supported-version-list).
+**Error message 1**
 
-Or
+**K8sVersionNotSupported:** Managed cluster `<ClusterName>` is on version 1.25.6 which is not supported in this region. Please use the `[azaks get-versions]` command to get the supported version list in this region. For more information, see [Supported Kubernetes versions in Azure Kubernetes Service (AKS)](https://aka.ms/supported-version-list).
 
-**OperationNotAllowed:** Upgrading Kubernetes version 1.24.9 to 1.26.6
-is not allowed. Available upgrades: [1.29.15 1.29.14 1.29.13 1.29.12
-1.29.11 1.29.10 1.29.9 1.29.8 1.29.7 1.29.6 1.29.5 1.29.4 1.29.2
-1.29.0]. For more information, see [AKS supported Kubernetes versions](https://aka.ms/aks-supported-k8s-ver) for version
-details.
+**Error message 2**
 
-Or
+**OperationNotAllowed:** Upgrading Kubernetes version 1.24.9 to 1.26.6 is not allowed. Available upgrades: [1.29.15 1.29.14 1.29.13 1.29.12 1.29.11 1.29.10 1.29.9 1.29.8 1.29.7 1.29.6 1.29.5 1.29.4 1.29.2 1.29.0]. For more information, see [AKS supported Kubernetes versions](https://aka.ms/aks-supported-k8s-ver) for version details.
 
-**NodePoolMcVersionIncompatible:** Node pool version 1.24.9 and control
-plane version 1.29.15 is incompatible. Minor version of node pool cannot
-be more than 3 versions less than control plane's version. Minor version
-of node pool is 24 and control plane is 29. For more information, see
-[AKS upgrade version skew policy](https://aka.ms/aks/UpgradeVersionRules).
+**Error message 3**
+
+**NodePoolMcVersionIncompatible:** Node pool version 1.24.9 and control plane version 1.29.15 is incompatible. Minor version of node pool cannot be more than 3 versions less than control plane's version. Minor version of node pool is 24 and control plane is 29. For more information, see [AKS upgrade version skew policy](https://aka.ms/aks/UpgradeVersionRules).
 
 ## Cause
 
-The upgrade is not allowed due to one or more of the following reasons:
+The upgrade is not allowed for 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.
+- The target Kubernetes version (for example, 1.26 or 1.25) 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.
+- 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.
 
-- A control plane and node pool version skew (**NodePoolMcVersionIncompatible**) occurred when attempting to upgrade only the control plane while the nodepool version is too far behind causing a big gap such that the node pool version is more than three minor versions behind the control plane version.
+- A control plane and node pool version skew (**NodePoolMcVersionIncompatible**) occurs if you try to upgrade only the control plane. In this situation, the node pool version becomes more than three minor versions behind the control plane version. A gap of this size or greater causes the error.
 
-To understand more about these errors, you can refer to following articles:
+To understand more about these errors, refer to following articles:
 
 - [AKS supported Kubernetes versions](https://aka.ms/aks-supported-k8s-ver)
 - [AKS upgrade version skew policy](https://aka.ms/aks/UpgradeVersionRules)
 
 ## Solution
 
-### Step 1: Confirm the current version and available upgrade paths
+### Step 1: Verify the current version and available upgrade paths
 
-Run the following command to view the current Kubernetes version and supported upgrade targets:
+To view the current Kubernetes version and supported upgrade targets, run the following command:
 
 ```azurecli
 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 like 1.25.x, 1.26.x, or 1.27.x are missing, this indicates that those versions are deprecated in your region.
+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, this indicates that
+those versions are deprecated in your region.
 
-### Step 2: Attempt full upgrade (control plane and node pool together)
+### Step 2: Try a full upgrade (control plane and node pool together)
 
-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 not be allowed. Instead, upgrade both the control plane and node pool together:
+Because of the version skew policy ("control planes cannot be more than 3 minor versions ahead of node pools"),
+a separate control-plane-only upgrade might not be allowed. Instead, upgrade both the control plane and node pool together:
 
 ```azurecli
 az aks upgrade --resource-group <RG> --name <ClusterName> --kubernetes-version <available upgrade version> --yes
 ```
 
-This will ensure compliance with the version skew policy, use of a supported Kubernetes version and upgrade of both components in a coordinated manner.
+This method makes sure that the following conditions apply:
+
+- You're in compliance with the version skew policy.
+- You use a supported Kubernetes version.
+- You upgrade both components in a coordinated manner.
 
-### Additional Tips
+### Additional tips
 
-- Always validate supported versions in your region using:
+- Always validate supported versions in your region by using the following command:
 
 ```azurecli
 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. In this situation, AKS might enforce an immediate skip to a supported long-term version (for example, to version 1.29).
 
-- **For AKS clusters running significantly outdated Kubernetes versions**, the recommended best practices include following:
+- In the case of AKS clusters that are running significantly outdated Kubernetes versions, the recommended best practices are as follows:
 
-  - **Create a New Cluster:** Spin up a new AKS cluster with a supported
-    Kubernetes version.
+  - **Create a new cluster:** create an AKS cluster by using 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 avoid potential issues.
 
-  - **Backup and Validate Data:** Ensure all data is backed up and validated
-    before migration.
+  - **Back up and validate data:** Make sure that all data is backed up and validated before a 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.
 
 [!INCLUDE [azure-help-support](../../../includes/azure-help-support.md)]