diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 1ef381d..0cb84fd 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -3,10 +3,10 @@ name: ci
 on:
   push:
     branches:
-      - main
+      - master
   pull_request:
     branches:
-      - main
+      - master
   workflow_dispatch:
   schedule:
     - cron: "0 5 * * *"
@@ -21,6 +21,7 @@ jobs:
           - ubuntu-latest
           - macos-latest
         ocaml-compiler:
+          - ocaml-base-compiler.5.3.0~beta1
           - 5.2.x
           - 5.1.x
           - 5.0.x
diff --git a/CHANGELOG.md b/CHANGELOG.md
index ebb05f5..cede5c7 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,9 @@
+## 1.3.3 - 2024-11-10
+
+### Added
+
+* Add OCaml 5.3 support (#73).
+
 ## 1.3.2 - 2024-02-25
 
 ### Added
diff --git a/src/debugger/inspect/ctype.ml b/src/debugger/inspect/ctype.ml
new file mode 100644
index 0000000..6e32c38
--- /dev/null
+++ b/src/debugger/inspect/ctype.ml
@@ -0,0 +1,5 @@
+include Ocaml_common.Ctype
+
+[%%if ocaml_version < (5, 3, 0)]
+let duplicate_type = correct_levels
+[%%endif]
diff --git a/src/debugger/inspect/value_scope.ml b/src/debugger/inspect/value_scope.ml
index 34436aa..177905c 100644
--- a/src/debugger/inspect/value_scope.ml
+++ b/src/debugger/inspect/value_scope.ml
@@ -49,7 +49,7 @@ class local_scope_value ~scene ~frame ~kind () =
                      match typenv |> Typenv.find_value (Path.Pident id) with
                      | exception Not_found -> None
                      | { val_type; val_kind; _ } ->
-                         let ty = Ctype.correct_levels val_type in
+                         let ty = Ctype.duplicate_type val_type in
                          Some (Ident.name id, val_kind, ty, pos))
               |> Array.of_seq,
               match (frame.index, event.ev_kind) with