diff --git a/specification/eventgrid/data-plane/Microsoft.Communication/stable/2018-01-01/AzureCommunicationServices.json b/specification/eventgrid/data-plane/Microsoft.Communication/stable/2018-01-01/AzureCommunicationServices.json
index 8d83d520a87a..1b59779ce818 100644
--- a/specification/eventgrid/data-plane/Microsoft.Communication/stable/2018-01-01/AzureCommunicationServices.json
+++ b/specification/eventgrid/data-plane/Microsoft.Communication/stable/2018-01-01/AzureCommunicationServices.json
@@ -238,7 +238,8 @@
         },
         "version": {
           "description": "The version of the thread",
-          "type": "integer"
+          "type": "integer",
+          "format": "int64"
         }
       }
     },
@@ -273,7 +274,8 @@
         },
         "version": {
           "description": "The version of the message",
-          "type": "integer"
+          "type": "integer",
+          "format": "int64"
         }
       }
     },