diff --git a/gramjs/tl/api.d.ts b/gramjs/tl/api.d.ts
index 39d4de19..babe018e 100644
--- a/gramjs/tl/api.d.ts
+++ b/gramjs/tl/api.d.ts
@@ -9776,7 +9776,7 @@ export namespace Api {
                 phoneNumber: string;
                 phoneCodeHash: string;
                 firstName: string;
-                lastName: string;
+                lastName?: string;
             }>,
             auth.TypeAuthorization
         > {