diff --git a/.github/scripts/cygwin.cmd b/.github/scripts/cygwin.cmd
index c60835be74a..cfc9ee38a52 100644
--- a/.github/scripts/cygwin.cmd
+++ b/.github/scripts/cygwin.cmd
@@ -83,10 +83,10 @@ md %CYGWIN_ROOT%
 :: Download the required setup program: the mingw-w64 compilers are only
 :: installed with Cygwin64.
 if "%1" equ "x86_64-pc-cygwin" (
-  curl -sLo %CYGWIN_ROOT%\setup.exe https://cygwin.com/setup-x86_64.exe
+  curl -fsSLo %CYGWIN_ROOT%\setup.exe https://cygwin.com/setup-x86_64.exe
   set CYGWIN_PACKAGES=,mingw64-i686-gcc-core=14.3.0-0.1,mingw64-x86_64-gcc-core=14.3.0-0.1,mingw64-i686-gcc-g++=14.3.0-0.1,mingw64-x86_64-gcc-g++=14.3.0-0.1
 ) else (
-  curl -sLo %CYGWIN_ROOT%\setup.exe https://cygwin.com/setup-x86.exe
+  curl -fsSLo %CYGWIN_ROOT%\setup.exe https://cygwin.com/setup-x86.exe
   set CYGWIN_PACKAGES=
 )
 
diff --git a/.github/scripts/main/ocaml-cache.sh b/.github/scripts/main/ocaml-cache.sh
index 8effee34363..355e2e73bc1 100644
--- a/.github/scripts/main/ocaml-cache.sh
+++ b/.github/scripts/main/ocaml-cache.sh
@@ -42,10 +42,11 @@ esac
 FLEXDLL_VERSION=0.43
 MINGW_W64_VERSION=12.0.0
 
-curl -sLO "https://github.com/ocaml/ocaml/archive/refs/tags/${OCAML_VERSION}.tar.gz"
+curl -fsSLO "https://github.com/ocaml/ocaml/archive/refs/tags/${OCAML_VERSION}.tar.gz" || \
+curl -fsSLO "https://github.com/ocaml/ocaml/archive/refs/heads/${OCAML_VERSION}.tar.gz"
 if [[ $PLATFORM = 'Windows' ]] ; then
-  curl -sLO "https://github.com/ocaml/flexdll/archive/refs/tags/$FLEXDLL_VERSION.tar.gz"
-  curl -sLO "https://github.com/mingw-w64/mingw-w64/archive/refs/tags/v${MINGW_W64_VERSION}.tar.gz"
+  curl -fsSLO "https://github.com/ocaml/flexdll/archive/refs/tags/$FLEXDLL_VERSION.tar.gz"
+  curl -fsSLO "https://github.com/mingw-w64/mingw-w64/archive/refs/tags/v${MINGW_W64_VERSION}.tar.gz"
 fi
 
 tar -xzf "$OCAML_VERSION.tar.gz"
@@ -61,7 +62,7 @@ esac
 
 cd "ocaml-$OCAML_VERSION"
 for sha in $PATCHES; do
-  curl -sL "https://github.com/ocaml/ocaml/commit/$sha.patch" -o "../$sha.patch"
+  curl -fsSL "https://github.com/ocaml/ocaml/commit/$sha.patch" -o "../$sha.patch"
   patch -p1 -i "../$sha.patch"
 done
 
@@ -96,8 +97,8 @@ OCAML_BRANCH="${OCAML_BRANCH/./}"
 if [[ $OPAM_TEST -ne 1 ]] ; then
   if [[ -e configure.ac ]]; then
     CONFIGURE_SWITCHES="--disable-debugger --disable-debug-runtime --disable-ocamldoc --disable-installing-bytecode-programs --disable-installing-source-artifacts"
-    if [[ $OCAML_BRANCH -eq 408 ]]; then
-      curl -L https://github.com/ocaml/ocaml/commit/c8ee39b320207717135d88cad67fb65d0901d6b6.patch -o pr8858.patch
+    if [[ $OCAML_BRANCH = 408 ]]; then
+      curl -fsSL https://github.com/ocaml/ocaml/commit/c8ee39b320207717135d88cad67fb65d0901d6b6.patch -o pr8858.patch
       patch -p1 -i pr8858.patch
       CONFIGURE_SWITCHES="$CONFIGURE_SWITCHES --disable-graph-lib"
     fi
diff --git a/.github/scripts/main/opam-bs-cache.sh b/.github/scripts/main/opam-bs-cache.sh
index 8db122194c5..dd723be07c6 100644
--- a/.github/scripts/main/opam-bs-cache.sh
+++ b/.github/scripts/main/opam-bs-cache.sh
@@ -12,7 +12,7 @@ if [ "$os" = "darwin" ] ; then
   os=macos
 fi
 
-curl -sL -o $OPAM_LOCAL/bin/opam-bootstrap \
+curl -fsSL -o $OPAM_LOCAL/bin/opam-bootstrap \
   "https://github.com/ocaml/opam/releases/download/$OPAMBSVERSION/opam-$OPAMBSVERSION-$(uname -m)-$os"
 cp -f $OPAM_LOCAL/bin/opam-bootstrap $OPAM_LOCAL/bin/opam
 chmod a+x $OPAM_LOCAL/bin/opam
diff --git a/.github/scripts/main/preamble.sh b/.github/scripts/main/preamble.sh
index 4d3b9062bf9..53865eba2a2 100644
--- a/.github/scripts/main/preamble.sh
+++ b/.github/scripts/main/preamble.sh
@@ -22,7 +22,7 @@ OPAM_DOC=${OPAM_DOC:-0}
 OPAM_DEPENDS=${OPAM_DEPENDS:-0}
 OPAM_UPGRADE=${OPAM_UPGRADE:-0}
 
-OPAM_REPO_MAIN=https://github.com/ocaml/opam-repository.git
+OPAM_REPO_MAIN=https://github.com/kit-ty-kate/opam-repository.git
 
 OPAM12CACHE=`eval echo $OPAM12CACHE`
 OPAMBSROOT=`eval echo $OPAMBSROOT`
diff --git a/.github/scripts/main/upgrade.sh b/.github/scripts/main/upgrade.sh
index 7435f698b57..2d8731dc4e6 100644
--- a/.github/scripts/main/upgrade.sh
+++ b/.github/scripts/main/upgrade.sh
@@ -16,7 +16,7 @@ if [[ ! -f $OPAM12 ]]; then
   if [ "$RUNNER_OS" = "macOS" ]; then
     os="Darwin"
   fi
-  curl -sL "https://github.com/ocaml/opam/releases/download/1.2.2/opam-1.2.2-x86_64-$os" -o $OPAM12
+  curl -fsSL "https://github.com/ocaml/opam/releases/download/1.2.2/opam-1.2.2-x86_64-$os" -o $OPAM12
   chmod +x $OPAM12
 fi
 export OPAMROOT=/tmp/opamroot
diff --git a/.github/scripts/scripts/hygiene.sh b/.github/scripts/scripts/hygiene.sh
index 2d41b6c3fca..8c7a8ed811e 100644
--- a/.github/scripts/scripts/hygiene.sh
+++ b/.github/scripts/scripts/hygiene.sh
@@ -32,7 +32,7 @@ if [[ $GITHUB_EVENT_NAME = 'pull_request' ]]; then
       fi
       URL="$OPAM_BIN_URL_BASE$tag/opam-$tag-$platform"
       echo "Downloading $URL"
-      check=$(curl -Ls "$URL" | sha512sum | cut -d' ' -f1)
+      check=$(curl -fsSL "$URL" | sha512sum | cut -d' ' -f1)
       if [[ $check = $sha ]] ; then
         echo "         as expected ($sha)"
       else
diff --git a/.github/workflows/ci.ml b/.github/workflows/ci.ml
index 24a9873597b..389508e564e 100644
--- a/.github/workflows/ci.ml
+++ b/.github/workflows/ci.ml
@@ -14,16 +14,17 @@
 open Lib
 
 let latest_ocaml4 = "4.14.2"
-let latest_ocaml5 = "5.3.0" (* Add this number to ocamls below when the next version comes out *)
+let latest_ocaml5 = "5.4.0-beta2" (* Add this number to ocamls below when the next version comes out *)
 let ocamls = [
   (* Fully supported versions *)
   "4.08.1"; "4.09.1"; "4.10.2"; "4.11.2"; "4.12.1"; "4.13.1";
-  "5.0.0"; "5.1.1"; "5.2.1";
+  "5.0.0"; "5.1.1"; "5.2.1"; "5.3.0"; "trunk";
 
   (* The last elements of the list after 4.14 will be used as default versions *)
   latest_ocaml4; latest_ocaml5;
 ]
-let start_latests_ocaml = (4, 14)
+let start_latests_ocaml = latest_ocaml4
+let oldest_ocamlv = List.hd ocamls
 
 (* Entry point for the workflow. Workflows are specified as continuations where
    each job is passed as a continuation to the [workflow], terminated with
@@ -69,12 +70,9 @@ jobs:
 
 let end_workflow ~oc:_ ~workflow:_ = ()
 
-let ocamls =
-  List.map (fun v -> Scanf.sscanf v "%u.%u.%u" (fun major minor _ -> ((major, minor), v))) ocamls
-
 let platform_ocaml_matrix ?(dir=List.drop_while) ~fail_fast start_version =
   (fail_fast,
-   [("ocamlv", List.map snd (dir (fun ocaml -> fst ocaml <> start_version) ocamls))],
+   [("ocamlv", dir (fun ocaml -> not (String.equal ocaml start_version)) ocamls)],
    [])
 
 let git_lf_checkouts ?(title="Configure Git") ?cond ?shell () =
@@ -315,7 +313,7 @@ let main_build_job ~analyse_job ~cygwin_job ?section runner start_version ~oc ~w
           "x86_64-pc-windows"
         ] in
         let ocaml5 = [
-          (* "x86_64-pc-cygwin"; *) (* TODO: Restore Cygwin + OCaml 5.3 when C++ support is fixed and released *)
+          "x86_64-pc-cygwin";
           "x86_64-w64-mingw32";
           "x86_64-pc-windows";
         ] in
@@ -543,9 +541,9 @@ let main oc : unit =
     ("OPAMBSROOT", "~/.cache/.opam.cached");
     ("OPAM12CACHE", "~/.cache/opam1.2/cache");
     (* These should be identical to the values in appveyor.yml *)
-    ("OPAM_REPO", "https://github.com/ocaml/opam-repository.git");
-    ("OPAM_TEST_REPO_SHA", "3dab8c734b15bf2b5c1d8b99bb134f51361a6bee");
-    ("OPAM_REPO_SHA", "3dab8c734b15bf2b5c1d8b99bb134f51361a6bee");
+    ("OPAM_REPO", "https://github.com/kit-ty-kate/opam-repository.git");
+    ("OPAM_TEST_REPO_SHA", "2e86b4d508e56b2affe6458ef776e20b9b4ec253");
+    ("OPAM_REPO_SHA", "2e86b4d508e56b2affe6458ef776e20b9b4ec253");
     ("SOLVER", "");
     (* Cygwin configuration *)
     ("CYGWIN_MIRROR", "http://mirrors.kernel.org/sourceware/cygwin/");
@@ -562,7 +560,7 @@ let main oc : unit =
   workflow ~oc ~env "Builds, tests & co"
   ++ analyse_job ~keys ~platforms:[Linux]
   @@ fun analyse_job -> cygwin_job ~analyse_job
-  @@ fun cygwin_job -> main_build_job ~analyse_job ~cygwin_job ~section:"Build" Linux (4, 08)
+  @@ fun cygwin_job -> main_build_job ~analyse_job ~cygwin_job ~section:"Build" Linux oldest_ocamlv
   @@ fun build_linux_job -> main_build_job ~analyse_job ~cygwin_job Windows start_latests_ocaml
   @@ fun build_windows_job -> main_build_job ~analyse_job ~cygwin_job MacOS start_latests_ocaml
   @@ fun build_macOS_job -> main_test_job ~analyse_job ~build_linux_job ~build_windows_job ~build_macOS_job ~section:"Opam tests" Linux
diff --git a/.github/workflows/depexts.yml b/.github/workflows/depexts.yml
index 2a5f863c35c..35d91b85d51 100644
--- a/.github/workflows/depexts.yml
+++ b/.github/workflows/depexts.yml
@@ -18,8 +18,8 @@ defaults:
 
 env:
   OPAMVERSION: 2.4.1
-  OPAM_REPO: https://github.com/ocaml/opam-repository.git
-  OPAM_REPO_SHA: 3dab8c734b15bf2b5c1d8b99bb134f51361a6bee
+  OPAM_REPO: https://github.com/kit-ty-kate/opam-repository.git
+  OPAM_REPO_SHA: 2e86b4d508e56b2affe6458ef776e20b9b4ec253
 
 jobs:
   opam-cache:
diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index d3671d41a1c..e3b679ff8bb 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -25,9 +25,9 @@ env:
   OPAMBSVERSION: 2.1.0
   OPAMBSROOT: ~/.cache/.opam.cached
   OPAM12CACHE: ~/.cache/opam1.2/cache
-  OPAM_REPO: https://github.com/ocaml/opam-repository.git
-  OPAM_TEST_REPO_SHA: 3dab8c734b15bf2b5c1d8b99bb134f51361a6bee
-  OPAM_REPO_SHA: 3dab8c734b15bf2b5c1d8b99bb134f51361a6bee
+  OPAM_REPO: https://github.com/kit-ty-kate/opam-repository.git
+  OPAM_TEST_REPO_SHA: 2e86b4d508e56b2affe6458ef776e20b9b4ec253
+  OPAM_REPO_SHA: 2e86b4d508e56b2affe6458ef776e20b9b4ec253
   SOLVER:
   CYGWIN_MIRROR: http://mirrors.kernel.org/sourceware/cygwin/
   CYGWIN_ROOT: D:\cygwin
@@ -106,7 +106,7 @@ jobs:
     needs: Analyse
     strategy:
       matrix:
-        ocamlv: [ 4.08.1, 4.09.1, 4.10.2, 4.11.2, 4.12.1, 4.13.1, 5.0.0, 5.1.1, 5.2.1, 4.14.2, 5.3.0 ]
+        ocamlv: [ 4.08.1, 4.09.1, 4.10.2, 4.11.2, 4.12.1, 4.13.1, 5.0.0, 5.1.1, 5.2.1, 5.3.0, trunk, 4.14.2, 5.4.0-beta2 ]
       fail-fast: true
     steps:
     - name: Install bubblewrap
@@ -159,12 +159,15 @@ jobs:
           - host: x86_64-pc-windows
             build: x86_64-pc-cygwin
             ocamlv: 4.14.2
+          - host: x86_64-pc-cygwin
+            build: x86_64-pc-cygwin
+            ocamlv: 5.4.0-beta2
           - host: x86_64-w64-mingw32
             build: x86_64-pc-cygwin
-            ocamlv: 5.3.0
+            ocamlv: 5.4.0-beta2
           - host: x86_64-pc-windows
             build: x86_64-pc-cygwin
-            ocamlv: 5.3.0
+            ocamlv: 5.4.0-beta2
       fail-fast: false
     defaults:
       run:
@@ -250,7 +253,7 @@ jobs:
     needs: Analyse
     strategy:
       matrix:
-        ocamlv: [ 4.14.2, 5.3.0 ]
+        ocamlv: [ 4.14.2, 5.4.0-beta2 ]
       fail-fast: true
     steps:
     - name: Install GNU patch
@@ -288,7 +291,7 @@ jobs:
     needs: [ Analyse, Build-Linux ]
     strategy:
       matrix:
-        ocamlv: [ 4.14.2, 5.3.0 ]
+        ocamlv: [ 4.14.2, 5.4.0-beta2 ]
       fail-fast: false
     env:
       OPAM_TEST: 1
@@ -345,7 +348,7 @@ jobs:
     needs: Analyse
     strategy:
       matrix:
-        ocamlv: [ 4.14.2, 5.3.0 ]
+        ocamlv: [ 4.14.2, 5.4.0-beta2 ]
       fail-fast: false
     env:
       OPAM_TEST: 1
@@ -434,7 +437,7 @@ jobs:
     needs: [ Analyse, Build-Linux ]
     strategy:
       matrix:
-        ocamlv: [ 4.14.2, 5.3.0 ]
+        ocamlv: [ 4.14.2, 5.4.0-beta2 ]
       fail-fast: false
     env:
       OPAM_DOC: 1
@@ -491,7 +494,7 @@ jobs:
     strategy:
       matrix:
         solver: [ z3, 0install ]
-        ocamlv: [ 4.14.2, 5.3.0 ]
+        ocamlv: [ 4.14.2, 5.4.0-beta2 ]
       fail-fast: false
     env:
       SOLVER: ${{ matrix.solver }}
@@ -541,7 +544,7 @@ jobs:
     strategy:
       matrix:
         solver: [ z3, 0install ]
-        ocamlv: [ 4.14.2, 5.3.0 ]
+        ocamlv: [ 4.14.2, 5.4.0-beta2 ]
       fail-fast: false
     env:
       SOLVER: ${{ matrix.solver }}
@@ -589,7 +592,7 @@ jobs:
     needs: [ Analyse, Build-Linux ]
     strategy:
       matrix:
-        ocamlv: [ 4.14.2, 5.3.0 ]
+        ocamlv: [ 4.14.2, 5.4.0-beta2 ]
       fail-fast: false
     steps:
     - name: Install bubblewrap
@@ -624,7 +627,7 @@ jobs:
     needs: [ Analyse, Build-macOS ]
     strategy:
       matrix:
-        ocamlv: [ 4.14.2, 5.3.0 ]
+        ocamlv: [ 4.14.2, 5.4.0-beta2 ]
       fail-fast: false
     steps:
     - name: Checkout tree
@@ -694,7 +697,7 @@ jobs:
     needs: [ Analyse, Build-Linux ]
     strategy:
       matrix:
-        ocamlv: [ 4.14.2, 5.3.0 ]
+        ocamlv: [ 4.14.2, 5.4.0-beta2 ]
       fail-fast: false
     env:
       OPAM_DEPENDS: 1
diff --git a/src/client/opamTreeCommand.ml b/src/client/opamTreeCommand.ml
index e8fd1c49a45..ee3c7169258 100644
--- a/src/client/opamTreeCommand.ml
+++ b/src/client/opamTreeCommand.ml
@@ -12,8 +12,8 @@
 open OpamTypes
 open OpamStateTypes
 
-type deps
-type revdeps
+type deps = private [`deps]
+type revdeps = private [`revdeps]
 type 'a node =
   | Root of package
   | Dependency : {