diff --git a/pkgs/development/ocaml-modules/index/default.nix b/pkgs/development/ocaml-modules/index/default.nix
index d0857f7ef0a1..f4b1844d684c 100644
--- a/pkgs/development/ocaml-modules/index/default.nix
+++ b/pkgs/development/ocaml-modules/index/default.nix
@@ -1,18 +1,18 @@
-{ lib, fetchurl, buildDunePackage, fmt, logs, stdlib-shims }:
+{ lib, fetchurl, buildDunePackage, fmt, logs, mtime, stdlib-shims }:
 
 buildDunePackage rec {
   pname = "index";
-  version = "1.2.0";
+  version = "1.2.1";
 
   minimumOCamlVersion = "4.07";
 
   src = fetchurl {
     url = "https://github.com/mirage/index/releases/download/${version}/index-${version}.tbz";
-    sha256 = "0d44s1d2mpxvpg0zh57c928wf1w1wd33l1fw5r62al5zmi710ff6";
+    sha256 = "1a9b6rsazrjy07syxl9ix5002i95mlvx5vk7nl2x9cs6s0zw906d";
   };
 
   buildInputs = [ stdlib-shims ];
-  propagatedBuildInputs = [ fmt logs ];
+  propagatedBuildInputs = [ fmt logs mtime ];
 
   meta = {
     homepage = "https://github.com/mirage/index";