diff --git a/docs/index.rst b/docs/index.rst
index 920ddf60..a574f29c 100644
--- a/docs/index.rst
+++ b/docs/index.rst
@@ -42,7 +42,8 @@ Also, you can join the developers' `mailing list
 
 Changes
 -------
-See the :doc:`changelog` for a full list of changes to MongoEngine.
+See the :doc:`changelog` for a full list of changes to MongoEngine and
+:doc:`upgrade` for upgrade information.
 
 .. toctree::
    :hidden:
diff --git a/mongoengine/fields.py b/mongoengine/fields.py
index cf72e78b..68d7acee 100644
--- a/mongoengine/fields.py
+++ b/mongoengine/fields.py
@@ -597,7 +597,9 @@ class ReferenceField(BaseField):
     access (lazily).
 
     Use the `reverse_delete_rule` to handle what should happen if the document
-    the field is referencing is deleted.
+    the field is referencing is deleted.  EmbeddedDocuments, DictFields and
+    MapFields do not support reverse_delete_rules and an `InvalidDocumentError`
+    will be raised if trying to set on one of these Document / Field types.
 
     The options are: