Update enable-key-vault-virtual-machine.md

Author: hirenshah1

articles/cloud-services-extended-support/enable-key-vault-virtual-machine.md

@@ -12,6 +12,9 @@ ms.date: 07/24/2024
 
 # Apply the Key Vault Virtual Machine (VM) extension to Azure Cloud Services (extended support)
 
+> [!IMPORTANT]
+> As of March 31, 2025, cloud Services (classic) is deprecated and will be fully retired on March 31, 2027. [Learn more](https://aka.ms/csesretirement) about this deprecation and [how to migrate](https://aka.ms/cses-retirement-march-2025).
+
 This article provides basic information about the Azure Key Vault VM extension for Windows and shows you how to enable it in Azure Cloud Services.
 
 ## What is the Key Vault VM extension?