diff --git a/reflection/reflection.fbs b/reflection/reflection.fbs
index 8fed025..d9e2dc4 100644
--- a/reflection/reflection.fbs
+++ b/reflection/reflection.fbs
@@ -24,12 +24,15 @@
     Vector,
     Obj,     // Used for tables & structs.
     Union,
-    Array
+    Array,
+
+    // Add any new type above this value.
+    MaxBaseType
 }
 
 table Type {
     base_type:BaseType;
-    element:BaseType = None;  // Only if base_type == Vector 
+    element:BaseType = None;  // Only if base_type == Vector
                               // or base_type == Array.
     index:int = -1;  // If base_type == Object, index into "objects" below.
                      // If base_type == Union, UnionType, or integral derived
@@ -71,6 +74,7 @@
     key:bool = false;
     attributes:[KeyValue];
     documentation:[string];
+    optional:bool = false;
 }
 
 table Object {  // Used for both tables and structs.