diff --git a/.github/workflows/more-ci.yml b/.github/workflows/more-ci.yml
index a67d56e..e59c6ec 100644
--- a/.github/workflows/more-ci.yml
+++ b/.github/workflows/more-ci.yml
@@ -31,6 +31,7 @@ jobs:
           - 5.4.x
           - 5.3.x
           - 5.2.x
+          - 4.14.x
         exclude:
           # We exclude the combination already tested in the 'ci' workflow.
           - os: ubuntu-latest
@@ -54,15 +55,21 @@ jobs:
       #     janestreet-bleeding: https://github.com/janestreet/opam-repository.git
       #     janestreet-bleeding-external: https://github.com/janestreet/opam-repository.git#external-packages
 
-      # Setting `(implicit_transitive_deps VALUE)` conditionally based on the compiler version.
-      - name: Edit dune-project
-        run: opam exec -- ocaml .github/workflows/edit_dune_project_dot_ml "${{ matrix.ocaml-compiler }}"
+      - name: Environment setup
+        run: |
+          if [ "${{ matrix.ocaml-compiler }}" = "4.14.x" ]; then
+            echo "PACKAGES=fpath-sexp0" >> "$GITHUB_ENV"
+            echo "OPAM_PACKAGES=./fpath-sexp0.opam" >> "$GITHUB_ENV"
+          else
+            echo "PACKAGES=fpath-sexp0,fpath-base,fpath-base-tests" >> "$GITHUB_ENV"
+            echo "OPAM_PACKAGES=./fpath-sexp0.opam ./fpath-base.opam ./fpath-base-tests.opam" >> "$GITHUB_ENV"
+          fi
 
       # We build and run tests for a subset of packages. More tests are run in
       # the development workflow and as part of the main CI job. These are the
       # tests that are checked for every combination of os and ocaml-compiler.
       - name: Install dependencies
-        run: opam install ./fpath-sexp0.opam ./fpath-base.opam ./fpath-base-tests.opam --deps-only --with-test
+        run: opam install ${{ env.OPAM_PACKAGES }} --deps-only --with-test
 
       - name: Build & Run tests
-        run: opam exec -- dune build @all @runtest -p fpath-sexp0,fpath-base,fpath-base-tests
+        run: opam exec -- dune build @all @runtest --only-packages=${{ env.PACKAGES }}
diff --git a/dune-workspace b/dune-workspace
new file mode 100644
index 0000000..53d6fbd
--- /dev/null
+++ b/dune-workspace
@@ -0,0 +1,12 @@
+(lang dune 3.20)
+
+(lock_dir
+ (repositories overlay upstream alpha mbarbin))
+
+(repository
+ (name mbarbin)
+ (url "git+https://github.com/mbarbin/opam-repository.git"))
+
+(repository
+ (name alpha)
+ (url "git+https://github.com/kit-ty-kate/opam-alpha-repository.git"))
diff --git a/dune-workspace-4.14 b/dune-workspace-4.14
new file mode 100644
index 0000000..fe1c72c
--- /dev/null
+++ b/dune-workspace-4.14
@@ -0,0 +1,13 @@
+(lang dune 3.20)
+
+(pkg enabled)
+
+(lock_dir
+ (repositories overlay upstream mbarbin)
+ (constraints
+  (ocaml
+   (= 4.14.2))))
+
+(repository
+ (name mbarbin)
+ (url "git+https://github.com/mbarbin/opam-repository.git"))
diff --git a/dune-workspace-5.2 b/dune-workspace-5.2
new file mode 100644
index 0000000..b89d1d5
--- /dev/null
+++ b/dune-workspace-5.2
@@ -0,0 +1,13 @@
+(lang dune 3.20)
+
+(pkg enabled)
+
+(lock_dir
+ (repositories overlay upstream mbarbin)
+ (constraints
+  (ocaml
+   (= 5.2.1))))
+
+(repository
+ (name mbarbin)
+ (url "git+https://github.com/mbarbin/opam-repository.git"))
diff --git a/dune-workspace-5.3 b/dune-workspace-5.3
new file mode 100644
index 0000000..9f241c8
--- /dev/null
+++ b/dune-workspace-5.3
@@ -0,0 +1,13 @@
+(lang dune 3.20)
+
+(pkg enabled)
+
+(lock_dir
+ (repositories overlay upstream mbarbin)
+ (constraints
+  (ocaml
+   (= 5.3.0))))
+
+(repository
+ (name mbarbin)
+ (url "git+https://github.com/mbarbin/opam-repository.git"))
diff --git a/dune-workspace-5.4 b/dune-workspace-5.4
new file mode 100644
index 0000000..27f9589
--- /dev/null
+++ b/dune-workspace-5.4
@@ -0,0 +1,17 @@
+(lang dune 3.20)
+
+(pkg enabled)
+
+(lock_dir
+ (repositories overlay upstream alpha mbarbin)
+ (constraints
+  (ocaml
+   (= 5.4.0))))
+
+(repository
+ (name mbarbin)
+ (url "git+https://github.com/mbarbin/opam-repository.git"))
+
+(repository
+ (name alpha)
+ (url "git+https://github.com/kit-ty-kate/opam-alpha-repository.git"))