diff --git a/misp-core-format/raw.md b/misp-core-format/raw.md
index 5a244ea..0d948b4 100755
--- a/misp-core-format/raw.md
+++ b/misp-core-format/raw.md
@@ -1296,6 +1296,12 @@ or parsing.
         "timestamp": {
           "type": "string"
         },
+        "first_seen": {
+          "type": "string"
+        },
+        "last_seen": {
+          "type": "string"
+        },
         "distribution": {
           "type": "string"
         },
@@ -1463,6 +1469,12 @@ or parsing.
         "timestamp": {
           "type": "string"
         },
+        "first_seen": {
+          "type": "string"
+        },
+        "last_seen": {
+          "type": "string"
+        },
         "comment": {
           "type": "string"
         },