diff --git a/.gitignore b/.gitignore
index c379efb..31e07fb 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,4 @@
 tests/**/results.json
 tests/**/.merlin.json
+tests/**/*-junit-results.xml
 **/_build/
diff --git a/Dockerfile b/Dockerfile
index ed50857..9ed0183 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,27 +1,27 @@
-FROM ocaml/opam:alpine-3.18-ocaml-4.14-afl AS builder
+FROM ocaml/opam:alpine-3.18-ocaml-5.2 AS builder
 
+ENV PATH="/home/opam/.opam/5.2/bin:${PATH}"
 
-RUN opam update \
- && opam install base core dune \
-  calendar react \
-  ounit ounit2 qcheck ezxmlm yojson \
-  ppx_deriving
-ENV PATH="/home/opam/.opam/4.14/bin:${PATH}"
+# We purposefully don't combine the opam update and opam install steps
+# to allow the opam update layer to be re-used in the runner image below 
+RUN opam update
+RUN opam install dune yojson ezxmlm
 
-COPY . .
-WORKDIR ./runner
-USER root
+WORKDIR /opt/test-runner
+COPY runner/ .
 RUN dune build
-USER $CONTAINER_USER_ID
 
-FROM ocaml/opam:alpine-3.18-ocaml-4.14-afl
-WORKDIR /opt/test-runner
+FROM ocaml/opam:alpine-3.18-ocaml-5.2 AS runner
 
+ENV PATH="/home/opam/.opam/5.2/bin:${PATH}"
 
-RUN opam update \
- && opam install dune ounit2 base qcheck react ppx_sexp_conv calendar ppx_deriving
+RUN opam update
+RUN opam install base ounit2 qcheck react calendar
+
+WORKDIR /opt/test-runner
+
+COPY --from=builder /opt/test-runner/_build/default/src/runner.exe bin/runner
 COPY . .
-COPY --from=builder /home/opam/runner/_build/default/src/runner.exe bin/runner
-ENV PATH="/home/opam/.opam/4.14/bin:${PATH}"
+
 USER root
 ENTRYPOINT ["/opt/test-runner/bin/run.sh"]
diff --git a/tests/example-empty-file/expected_results.json b/tests/example-empty-file/expected_results.json
index a6845a2..e7b2ffb 100644
--- a/tests/example-empty-file/expected_results.json
+++ b/tests/example-empty-file/expected_results.json
@@ -1,6 +1,6 @@
 {
   "version": 2,
   "status": "error",
-  "message": "File \"leap.ml\", line 1:\nError: The implementation leap.ml\n       does not match the interface .test.eobjs/byte/leap.cmi: \n       The value `leap_year' is required but not provided\n       File \"leap.mli\", line 1, characters 0-26: Expected declaration\nmake: *** [Makefile:4: test] Error 1",
+  "message": "File \"leap.ml\", line 1:\nError: The implementation \"leap.ml\" does not match the interface \"leap.ml\": \n       The value \"leap_year\" is required but not provided\n       File \"leap.mli\", line 1, characters 0-26: Expected declaration\nmake: *** [Makefile:4: test] Error 1",
   "tests": null
 }
\ No newline at end of file