Update application-gateway-tls-version-retirement.md

Author: jaesoni

articles/application-gateway/application-gateway-tls-version-retirement.md

@@ -5,7 +5,7 @@ services: application gateway
 author: jaesoni
 ms.service: azure-application-gateway
 ms.topic: concept-article
-ms.date: 05/15/2025
+ms.date: 07/18/2025
 ms.author: mbender
 ms.custom:
   - build-2025
@@ -86,6 +86,25 @@ You don't need to configure anything on your Application Gateway for the backend
 
 You must ensure that your servers in the backend pools are compatible with these updated protocol versions. This compatibility avoids any disruptions when establishing a TLS/HTTPS connection with those backend servers.
 
+## Identification methods
+
+### Metrics
+To determine whether clients connecting to your Application Gateway resource are utilising TLS 1.0 or 1.1, use the `Client TLS protocol` metric provided by Application Gateway. For further details, see the [metrics documentation](monitor-application-gateway-reference.md#metrics). You can view it from the Portal by following these steps.
+
+1. Go to the Application Gateway resource in the Azure portal.
+2. In the left menu pane, open the "Metrics" blade in Monitoring section.
+3. Select metric as `Client TLS protocol` from the dropdown.
+4. To view granular protocol version information, select "Apply splitting" and choose "TLS protocol".
+
+![A diagram showing metrics page with TLS version split for application gateway traffic.](media/application-gateway-tls-version-retirement/metric-tls-version.png)
+
+### Logs
+You can also refer to the [Application Gateway Access logs](monitor-application-gateway-reference.md#access-log-category) to view this information in the logs format.
+
+### Error information
+Once support for TLS versions 1.0 and 1.1 is discontinued, clients may encounter errors such as `curl: (35) error:0A000410:SSL routines::sslv3 alert handshake failure`. Depending on the browser being used, various messages indicating TLS handshake failures may be displayed.
+
+
 ## Next steps
 
 Learn about [TLS policy types and configurations](application-gateway-ssl-policy-overview.md)