Hi Rajesh,
Thank you for reaching out to the Microsoft Q&A platform.
From your question, it seems you're looking for the recent change in the Kubernetes version of your AKS cluster when it's set to Automatic upgrade.
To check this, log in to the Azure portal, go to your AKS cluster, and on the left-hand side, click on Cluster configuration. Then, click on View the AKS changelog to find the Kubernetes version of your AKS cluster.
Activity Logs: You can use the Azure portal to view activity logs for recent changes.
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Thank you.