diff --git a/docs/site/Understanding-the-differences.md b/docs/site/Understanding-the-differences.md
index 4e95fdab220d..0f0daa6f1e9f 100644
--- a/docs/site/Understanding-the-differences.md
+++ b/docs/site/Understanding-the-differences.md
@@ -42,6 +42,8 @@ model definitions, migrating their application incrementally.
 
 ## Concept/feature mapping
 
+{% include note.html content="See the [GitHub issue](https://github.com/strongloop/loopback-next/issues/1920) for a full list of features that have not been migrated to LoopBack 4." %}
+
 In Loopback 3.x (and earlier), models were responsible for both accessing data
 in other systems (databases, SOAP services, etc.) and providing the
 application's external REST API. This made it easy to quickly build a REST
diff --git a/docs/site/index.md b/docs/site/index.md
index d531048e1ac2..48f93abcae21 100644
--- a/docs/site/index.md
+++ b/docs/site/index.md
@@ -15,6 +15,8 @@ multiple repos, as in v3. However, examples and externally-developed components
 will be in separate repositories.
 '%}
 
+{% include important.html content="Certain features from LoopBack 3 may still be a work in progress or are not planned to be migrated to LoopBack 4. See [Understanding the differences](understanding-the-differences.md)." %}
+
 LoopBack is a highly extensible, open-source Node.js and TypeScript framework
 based on Express that enables you to quickly create APIs and microservices
 composed from backend systems such as databases and SOAP or REST services.