diff --git a/typings/hyper.d.ts b/typings/hyper.d.ts
index bd292d0b..dc2d442b 100644
--- a/typings/hyper.d.ts
+++ b/typings/hyper.d.ts
@@ -118,7 +118,7 @@ export type session = {
   pid: number | null;
   resizeAt?: number;
   rows: number | null;
-  search: Date | null;
+  search: ImmutableDate | null;
   shell: string | null;
   title: string;
   uid: string;