Fix #2457 (enum subtypes not working as map keys)
diff --git a/release-notes/VERSION-2.x b/release-notes/VERSION-2.x
index d7073fe..f3582ea 100644
--- a/release-notes/VERSION-2.x
+++ b/release-notes/VERSION-2.x
@@ -4,6 +4,11 @@
 === Releases === 
 ------------------------------------------------------------------------
 
+2.10.1 (not yet released)
+
+#2457: Extended enum values are not handled as enums when used as Map keys
+ (reported by Andrey K)
+
 2.10.0 (26-Sep-2019)
 
 #18: Make `JsonNode` serializable