diff --git a/ppx/test/react.t b/ppx/test/react.t
index 53833efd7..eb7c3f080 100644
--- a/ppx/test/react.t
+++ b/ppx/test/react.t
@@ -35,8 +35,8 @@ Demonstrate how to use the React JSX PPX
   // Generated by Melange
   'use strict';
   
-  var Belt__Belt_List = require("melange.belt/belt_List.js");
-  var JsxRuntime = require("react/jsx-runtime");
+  const Belt__Belt_List = require("melange.belt/belt_List.js");
+  const JsxRuntime = require("react/jsx-runtime");
   
   function X$App(Props) {
     return Belt__Belt_List.toArray(Belt__Belt_List.map({
@@ -52,7 +52,7 @@ Demonstrate how to use the React JSX PPX
                     })));
   }
   
-  var App = {
+  const App = {
     make: X$App
   };
   
diff --git a/reason-react.opam b/reason-react.opam
index 97f9d41ad..0fdfb3a82 100644
--- a/reason-react.opam
+++ b/reason-react.opam
@@ -19,7 +19,7 @@ bug-reports: "https://github.com/reasonml/reason-react/issues"
 depends: [
   "dune" {>= "3.9"}
   "ocaml"
-  "melange" {>= "3.0.0"}
+  "melange" {>= "4.0.0"}
   "reason-react-ppx" {= version}
   "reason" {>= "3.10.0"}
   "ocaml-lsp-server" {with-test}
diff --git a/test/blackbox-tests/useCallback.t b/test/blackbox-tests/useCallback.t
index 6580e25a0..58749b525 100644
--- a/test/blackbox-tests/useCallback.t
+++ b/test/blackbox-tests/useCallback.t
@@ -21,9 +21,9 @@
   // Generated by Melange
   'use strict';
   
-  var React = require("react");
+  const React = require("react");
   
-  var cb = React.useCallback((function (a, b) {
+  const cb = React.useCallback((function (a, b) {
           return a + b | 0;
         }), []);
   
@@ -42,9 +42,9 @@ Using an Uncurried function:
   // Generated by Melange
   'use strict';
   
-  var React = require("react");
+  const React = require("react");
   
-  var cb = React.useCallback((function (a, b) {
+  const cb = React.useCallback((function (a, b) {
           return a + b | 0;
         }), []);