diff --git a/src/backends/file_index.ts b/src/backends/file_index.ts
index c3089916..7be21dfb 100644
--- a/src/backends/file_index.ts
+++ b/src/backends/file_index.ts
@@ -15,7 +15,7 @@ import { decodeUTF8, encodeUTF8 } from '../utils.js';
  * @internal
  */
 export interface IndexData {
-	version: 1;
+	version: number;
 	entries: Record<string, StatsLike<number>>;
 }