diff --git a/index.d.ts b/index.d.ts
index ec2de46..dc03f4f 100644
--- a/index.d.ts
+++ b/index.d.ts
@@ -170,7 +170,7 @@ export interface SerializerOptions {
   visitor?: SerializerVisitor;
   dots?: boolean;
   metaTokens?: boolean;
-  indexes?: boolean;
+  indexes?: boolean | null;
 }
 
 // tslint:disable-next-line