diff --git a/bookstore/src/main/resources/messages.properties b/bookstore/src/main/resources/messages.properties
index 08b4d12..439de1f 100644
--- a/bookstore/src/main/resources/messages.properties
+++ b/bookstore/src/main/resources/messages.properties
@@ -60,7 +60,7 @@ page.text.list.delete              = Delete
 page.text.list.edit                = Edit
 page.text.list.json                = Get
 
-page.text.apiref.warning           = NOTE\:\ these direct JSON keys may differ in name \&\ count when comparing to publicly exposed JSON book data.
+page.text.apiref.warning           = NOTE\:\ these direct JSON keys may differ in name \&\ count when comparing to publicly exposed JSON book data due to custom JSON serializers used in Java code.
 
 page.text.apiref.endpoints         = REST API end points
 page.text.apiref.examples          = Direct search examples