add whats new info

Author: austinmccollum

articles/sentinel/whats-new.md

@@ -23,7 +23,16 @@ The listed features were released in the last three months. For information abou
 
 ## March 2024
 
-[Data connectors for Syslog and CEF based on Azure Monitor Agent now generally available (GA)](#data-connectors-for-syslog-and-cef-based-on-azure-monitor-agent-now-generally-available-ga)
+- [SIEM migration experience (preview)](#siem-migration-experience-preview)
+- [Data connectors for Syslog and CEF based on Azure Monitor Agent now generally available (GA)](#data-connectors-for-syslog-and-cef-based-on-azure-monitor-agent-now-generally-available-ga)
+
+### SIEM migration experience (preview)
+
+The new Microsoft Sentinel Migration experience helps customers and partners to automate the process of migrating their security monitoring use cases hosted in non-Microsoft products into Microsoft Sentinel.
+- This first version of the tool supports migrations from Splunk
+- Other products will be supported in the future.
+
+For more information, see [Migrate to Microsoft Sentinel with the SIEM migration experience](siem-migration.md)
 
 ### Data connectors for Syslog and CEF based on Azure Monitor Agent now generally available (GA)