diff --git a/CHANGELOG.md b/CHANGELOG.md
index 806b32fdb..7ff662d7b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -42,7 +42,7 @@ Thankyou! -->
 ## [Unreleased]
 
 ### Misc
-1. Added `email.subject` and `email.uid` as an Observable types - `type_id: 39` and `type_id: 40`. #1326
+1. Added `email.subject` and `email.uid` and `message_uid` as an Observable types - `type_id: 39`, `type_id: 40` and `type_id: 45`. #1326
 1. Added `process_entity.uid` as an Observable type - `type_id: 41` #1326
 1. Added `file_path_t` as an Observable type - `type_id: 42` and marked fields as this type #1326
     - `lineage` dictionary attribute
diff --git a/dictionary.json b/dictionary.json
index d38279ce3..232515e49 100644
--- a/dictionary.json
+++ b/dictionary.json
@@ -3312,7 +3312,8 @@
           "description": "RFC 5322",
           "url": "https://www.rfc-editor.org/rfc/rfc5322"
         }
-      ]
+      ],
+      "observable": 45
     },
     "metadata": {
       "caption": "Metadata",