diff --git a/specification/web/resource-manager/Microsoft.Web/stable/2018-02-01/CommonDefinitions.json b/specification/web/resource-manager/Microsoft.Web/stable/2018-02-01/CommonDefinitions.json
index da30e23dc16e..ecbefb2a6e4b 100644
--- a/specification/web/resource-manager/Microsoft.Web/stable/2018-02-01/CommonDefinitions.json
+++ b/specification/web/resource-manager/Microsoft.Web/stable/2018-02-01/CommonDefinitions.json
@@ -1308,7 +1308,9 @@
           "description": "Type of managed service identity.",
           "enum": [
             "SystemAssigned",
-            "UserAssigned"
+            "UserAssigned",
+            "SystemAssigned, UserAssigned",
+            "None"
           ],
           "type": "string",
           "x-ms-enum": {