Update whats-new.md

add container release

Author: jaep3347

articles/ai-services/document-intelligence/whats-new.md

@@ -27,6 +27,13 @@ Document Intelligence service is updated on an ongoing basis. Bookmark this page
 > [!IMPORTANT]
 > Preview API versions are retired once the GA API is released. The 2023-02-28-preview API version is retiring. If you're still using the preview API or the associated SDK versions, update your code to target the latest API version `2024-11-30 (GA)`. </br>
 
+## April 2025
+**Document Intelligence v4.0 container is now available! Currently, Layout model is the only supported model for v4.0 release.**
+<br>
+For more information, *see:*
+* [Install and run containers](containers/install-run.md?view=doc-intel-4.0.0&preserve-view=true)
+* [Container image tags](containers/image-tags.md?view=doc-intel-4.0.0&preserve-view=true)
+
 ## December 2024
 
 **Document Intelligence v4.0 programming language SDKs are now generally available (GA)**! <br><br>The latest client libraries default to the [**2024-11-30 REST API (GA)**](/rest/api/aiservices/operation-groups?view=rest-aiservices-v4.0%20(2024-11-30)&preserve-view=true) version of the service.<br><br>