diff --git a/pkgs/development/ocaml-modules/mirage-fs/default.nix b/pkgs/development/ocaml-modules/mirage-fs/default.nix
index d8cfddff313c..23c79c4a77d6 100644
--- a/pkgs/development/ocaml-modules/mirage-fs/default.nix
+++ b/pkgs/development/ocaml-modules/mirage-fs/default.nix
@@ -4,13 +4,13 @@
 
 buildDunePackage rec {
   pname = "mirage-fs";
-  version = "3.0.1";
+  version = "4.0.0";
 
   useDune2 = true;
 
   src = fetchurl {
     url = "https://github.com/mirage/mirage-fs/releases/download/v${version}/mirage-fs-v${version}.tbz";
-    sha256 = "0px18bgk528vr7iw78r0j3z4sdcz684sfcj47ibbly2adbvd64yk";
+    sha256 = "sha256-PYZ2HCPuxOv4FU7EHymsa1oIZU7q8TSzzRvlngYdZ3s=";
   };
 
   propagatedBuildInputs = [ cstruct fmt lwt mirage-device mirage-kv ];