Update README.md

Clarify Azure Monitor Support Policies

README.md

@@ -11,6 +11,10 @@ and succeeding. This PHP module will allow you to send telemetry of various
 kinds (event, trace, exception, etc.) to the Application Insights service where
 they can be visualized in the Azure Portal.
 
+## Status
+
+This SDK is NOT maintained or supported by Microsoft even though we've contributed to it in the past. Note that Azure Monitor only provides support when using the [supported SDKs](https://docs.microsoft.com/en-us/azure/azure-monitor/app/platforms#unsupported-community-sdks). We’re constantly assessing opportunities to expand our support for other languages, so follow our [GitHub Announcements](https://github.com/microsoft/ApplicationInsights-Announcements/issues) page to receive the latest SDK news.
+
 ## Requirements
 
 PHP version >=5.4.2 is supported.