diff --git a/src/types/mark.ts b/src/types/mark.ts
index b540643..e8ea327 100644
--- a/src/types/mark.ts
+++ b/src/types/mark.ts
@@ -9,7 +9,7 @@ export interface CurrentUserMark {
 }
 
 // Both PdfFileHash and FileHash currently exist.
-// It enables backward compatibility
+// It enables backward compatibility for Sigits created before January 2025
 export interface Mark {
   id: number
   npub: string