diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index c423196..e4638c7 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -24,7 +24,7 @@ jobs:
       - name: Set-up OCaml
         uses: ocaml/setup-ocaml@v2
         with:
-          ocaml-compiler: "ocaml-base-compiler.5.2.0"
+          ocaml-compiler: "ocaml-base-compiler.5.3.0~beta2"
 
       - run: opam install . --deps-only --with-test
 
diff --git a/dune-project b/dune-project
index 9e09f74..2e5c945 100644
--- a/dune-project
+++ b/dune-project
@@ -25,7 +25,7 @@
   ocaml
   dune
   (ocaml-base-compiler
-   (= 5.2.0))
+   (= 5.3.0~beta2))
   base
   js_of_ocaml
   js_of_ocaml-ppx
diff --git a/flake.lock b/flake.lock
index 53b312e..ba927b3 100644
--- a/flake.lock
+++ b/flake.lock
@@ -95,11 +95,11 @@
         "opam2json": "opam2json"
       },
       "locked": {
-        "lastModified": 1732617437,
-        "narHash": "sha256-jj25fziYrES8Ix6HkfSiLzrN6MZjiwlHUxFSIuLRjgE=",
+        "lastModified": 1733921344,
+        "narHash": "sha256-D4BFlu5VQCugO6wlze3BxDz5fkxoZishQTIwITLdSw8=",
         "owner": "tweag",
         "repo": "opam-nix",
-        "rev": "ea8b9cb81fe94e1fc45c6376fcff15f17319c445",
+        "rev": "43ec9805677c7ca3decd57f034c9a148bad5215c",
         "type": "github"
       },
       "original": {
@@ -127,11 +127,11 @@
     "opam-repository": {
       "flake": false,
       "locked": {
-        "lastModified": 1733656817,
-        "narHash": "sha256-ddoiIYY6AhWLUxkgtXhPbB7Du0OcHPyR4iEF/Tm8BsY=",
+        "lastModified": 1734474648,
+        "narHash": "sha256-lV68QTEyXgldXbn6WOAKdmLpIFxGr7SSSkoi0cFih6c=",
         "owner": "ocaml",
         "repo": "opam-repository",
-        "rev": "211ce1c3d5d6eb57dee3ca21cb1e4a16da41d01f",
+        "rev": "ca7f85630249c268f15747ccb64674fc5705dc94",
         "type": "github"
       },
       "original": {
diff --git a/flake.nix b/flake.nix
index 64325fa..31c3aa4 100644
--- a/flake.nix
+++ b/flake.nix
@@ -20,14 +20,18 @@
         pkgs = nixpkgs.legacyPackages.${system};
         on = opam-nix.lib.${system};
         devPackagesQuery = {
-          ocaml-lsp-server = "*";
-          ocamlformat = "*";
+          ocaml-lsp-server = "1.20.0~5.3preview";
+          ocamlformat = "0.27.0";
           utop = "*";
+          alcotest = "*";
         };
         query = devPackagesQuery // {
           ocaml-base-compiler = "*";
         };
-        scope = on.buildDuneProject { resolveArgs.with-test = true; } package ./. query;
+        scope = on.buildDuneProject {
+          # resolveArgs.with-test = true;
+          resolveArgs.env.enable-ocaml-beta-repository = true;
+        } package ./. query;
         overlay = final: prev: {
           ${package} = prev.${package}.overrideAttrs (_: {
             # Prevent the ocaml dependencies from leaking into dependent environments
diff --git a/react_trace.opam b/react_trace.opam
index 28e2501..b88693e 100644
--- a/react_trace.opam
+++ b/react_trace.opam
@@ -11,7 +11,7 @@ bug-reports: "https://github.com/React-Analysis/ReacttRace/issues"
 depends: [
   "ocaml"
   "dune" {>= "3.15"}
-  "ocaml-base-compiler" {= "5.2.0"}
+  "ocaml-base-compiler" {= "5.3.0~beta2"}
   "base"
   "js_of_ocaml"
   "js_of_ocaml-ppx"
@@ -42,7 +42,8 @@ build: [
 ]
 dev-repo: "git+https://github.com/React-Analysis/ReacttRace.git"
 pin-depends: [
-  [ "flow_parser.0.239.1" "git+https://github.com/facebook/flow#5d1b246a1ac8a8fc4e431b835ab8fb7f6f5ebd30" ]
+  [ "ppxlib.0.33.1~5.3preview" "git+https://github.com/ocaml-ppx/ppxlib#218347c59cb93e463f33f06801bd61cf47f46265" ]
+  [ "flow_parser.0.257.0" "git+https://github.com/Zeta611/flow#52bf15978715a096119d422145b1bb9f32a06804" ]
   [ "printbox.0.11" "git+https://github.com/c-cube/printbox#d49d9520e7d9e96121c13643cd3eaf8876389205" ]
   [ "printbox-text.0.11" "git+https://github.com/c-cube/printbox#d49d9520e7d9e96121c13643cd3eaf8876389205" ]
 ]
diff --git a/react_trace.opam.template b/react_trace.opam.template
index 4822aa9..c17bc8a 100644
--- a/react_trace.opam.template
+++ b/react_trace.opam.template
@@ -1,5 +1,6 @@
 pin-depends: [
-  [ "flow_parser.0.239.1" "git+https://github.com/facebook/flow#5d1b246a1ac8a8fc4e431b835ab8fb7f6f5ebd30" ]
+  [ "ppxlib.0.33.1~5.3preview" "git+https://github.com/ocaml-ppx/ppxlib#218347c59cb93e463f33f06801bd61cf47f46265" ]
+  [ "flow_parser.0.257.0" "git+https://github.com/Zeta611/flow#52bf15978715a096119d422145b1bb9f32a06804" ]
   [ "printbox.0.11" "git+https://github.com/c-cube/printbox#d49d9520e7d9e96121c13643cd3eaf8876389205" ]
   [ "printbox-text.0.11" "git+https://github.com/c-cube/printbox#d49d9520e7d9e96121c13643cd3eaf8876389205" ]
 ]