diff --git a/pkgs/development/tools/ocaml/js_of_ocaml/compiler.nix b/pkgs/development/tools/ocaml/js_of_ocaml/compiler.nix
index 5f81d23a42c4..49db27365957 100644
--- a/pkgs/development/tools/ocaml/js_of_ocaml/compiler.nix
+++ b/pkgs/development/tools/ocaml/js_of_ocaml/compiler.nix
@@ -12,7 +12,7 @@
   sedlex,
   version ?
     if lib.versionAtLeast ocaml.version "4.13" then
-      "6.4.0"
+      "6.4.1"
     else if lib.versionAtLeast ocaml.version "4.11" then
       "6.0.1"
     else
@@ -27,7 +27,7 @@ buildDunePackage {
     url = "https://github.com/ocsigen/js_of_ocaml/releases/download/${version}/js_of_ocaml-${version}.tbz";
     hash =
       {
-        "6.4.0" = "sha256-euIqflpsaqFKjiaV+mLGbzLLINsX8bRdwh6XAJNCFR8=";
+        "6.4.1" = "sha256-5Zu//K76ujGRYgVWUUt/U7sySeP4gaBw1yckI03/2Bk=";
         "6.3.2" = "sha256-qTr8llTsNGRwH7zg3M86i+uVCKyxLGBFd2vyzxBsq8A=";
         "6.2.0" = "sha256-fMZBd40bFyo1KogzPuDoxiE2WgrPzZuH44v9243Spdo=";
         "6.1.1" = "sha256-0x2kGq5hwCqqi01QTk6TcFIz0wPNgaB7tKxe7bA9YBQ=";