diff --git a/.github/workflows/ci.ml b/.github/workflows/ci.ml
index 95e71522813..55808f635b1 100644
--- a/.github/workflows/ci.ml
+++ b/.github/workflows/ci.ml
@@ -170,20 +170,15 @@ let get_cache name = get_cache_cont name Fun.id
 
 let cache ?cond ?(key_prefix="needs.Analyse") ?(check_only=false) name =
   get_cache_cont name (fun cache ->
-    let action =
-      if cache.force_gzip || check_only then
-        "ocaml-opam/cache@opam"
-      else
-        "actions/cache@v3"
-    in
+    let action = "actions/cache@v4" in
     let withs =
       if cache.force_gzip then
-        [("force-gzip", Literal ["true"])]
+        [("enableCrossOsArchive", Literal ["true"])]
       else
         [] in
     let withs =
       if check_only then
-        ("check-only", Literal ["true"]) :: withs
+        ("lookup-only", Literal ["true"]) :: withs
       else
         withs in
     let withs =
@@ -329,7 +324,7 @@ let main_build_job ~analyse_job ~cygwin_job ?section runner start_version ~oc ~w
          ~cond:(Predicate(true, EndsWith("matrix.host", "-pc-windows")))
          ~withs:[ ("name", Literal ["opam-exe-${{ matrix.host }}-${{ matrix.ocamlv }}-${{ matrix.build }}"]);
                   ("path", Literal ["D:\\Local\\bin\\opam.exe"; "D:\\Local\\bin\\opam-installer.exe"; "D:\\Local\\bin\\opam-putenv.exe"]) ]
-         "actions/upload-artifact@v3")
+         "actions/upload-artifact@v4")
     ++ only_on Windows (run "Test (basic - Cygwin)" ~cond:(Predicate(true, EndsWith("matrix.host", "-pc-cygwin"))) ["bash -exu .github/scripts/main/test.sh"])
     ++ only_on Windows (run "Test (basic - native Windows)" ~env:[("OPAMROOT", {|D:\a\opam\opam\.opam|})] ~shell:"cmd" ~cond:(Predicate(false, EndsWith("matrix.host", "-pc-cygwin")))
          ({|set Path=D:\Cache\ocaml-local\bin;%Path%|} ::
diff --git a/.github/workflows/depexts.yml b/.github/workflows/depexts.yml
index c28c2b1a684..7e59185114a 100644
--- a/.github/workflows/depexts.yml
+++ b/.github/workflows/depexts.yml
@@ -26,7 +26,7 @@ jobs:
     steps:
     - name: opam binary cache
       id: binary
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       with:
         path: binary/opam
         key: binary-${{ env.OPAMVERSION }}
@@ -43,9 +43,9 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - name: Checkout
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
     - name: opam binary cache
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       with:
         path: binary/opam
         key: binary-${{ env.OPAMVERSION }}
@@ -61,9 +61,9 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - name: Checkout
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
     - name: opam binary cache
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       with:
         path: binary/opam
         key: binary-${{ env.OPAMVERSION }}
@@ -79,9 +79,9 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - name: Checkout
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
     - name: opam binary cache
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       with:
         path: binary/opam
         key: binary-${{ env.OPAMVERSION }}
@@ -97,9 +97,9 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - name: Checkout
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
     - name: opam binary cache
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       with:
         path: binary/opam
         key: binary-${{ env.OPAMVERSION }}
@@ -115,9 +115,9 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - name: Checkout
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
     - name: opam binary cache
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       with:
         path: binary/opam
         key: binary-${{ env.OPAMVERSION }}
@@ -133,9 +133,9 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - name: Checkout
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
     - name: opam binary cache
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       with:
         path: binary/opam
         key: binary-${{ env.OPAMVERSION }}
@@ -151,9 +151,9 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - name: Checkout
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
     - name: opam binary cache
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       with:
         path: binary/opam
         key: binary-${{ env.OPAMVERSION }}
@@ -169,9 +169,9 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - name: Checkout
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
     - name: opam binary cache
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       with:
         path: binary/opam
         key: binary-${{ env.OPAMVERSION }}
@@ -187,9 +187,9 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - name: Checkout
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
     - name: opam binary cache
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       with:
         path: binary/opam
         key: binary-${{ env.OPAMVERSION }}
diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index e1928496e4a..4d7d9624140 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -66,14 +66,14 @@ jobs:
         echo opam-bs-cache=${{ hashFiles('.github/scripts/main/opam-bs-cache.sh', '*.opam', '.github/scripts/main/preamble.sh') }} >> $GITHUB_OUTPUT
     - name: src_ext/archives and opam-repository Cache
       id: archives
-      uses: ocaml-opam/cache@opam
+      uses: actions/cache@v4
       with:
         path: |
           src_ext/archives
           ~/opam-repository
         key: ${{ steps.keys.outputs.archives }}
-        check-only: true
-        force-gzip: true
+        lookup-only: true
+        enableCrossOsArchive: true
     - name: Create src_ext/archives and opam-repository cache
       if: steps.archives.outputs.cache-hit != 'true'
       run: bash -exu .github/scripts/main/archives-cache.sh
@@ -84,12 +84,12 @@ jobs:
     steps:
     - name: Cygwin64 Cache
       id: cygwin64
-      uses: ocaml-opam/cache@opam
+      uses: actions/cache@v4
       with:
         path: D:\Cache\cygwin\x86_64-pc-cygwin
         key: cygwin64-${{ needs.Analyse.outputs.cygwin }}
-        check-only: true
-        force-gzip: true
+        lookup-only: true
+        enableCrossOsArchive: true
     - name: Checkout tree
       if: steps.cygwin64.outputs.cache-hit != 'true'
       uses: actions/checkout@v4
@@ -115,16 +115,16 @@ jobs:
       uses: actions/checkout@v4
     - name: src_ext/archives and opam-repository Cache
       id: archives
-      uses: ocaml-opam/cache@opam
+      uses: actions/cache@v4
       with:
         path: |
           src_ext/archives
           ~/opam-repository
         key: ${{ needs.Analyse.outputs.archives }}
-        force-gzip: true
+        enableCrossOsArchive: true
     - name: OCaml ${{ matrix.ocamlv }} Cache
       id: ocaml-cache
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       with:
         path: ~/.cache/ocaml-local/**
         key: ${{ runner.os }}-ocaml-${{ matrix.ocamlv }}-${{ needs.Analyse.outputs.ocaml-cache }}
@@ -160,27 +160,27 @@ jobs:
     - name: Cygwin64 Cache
       id: cygwin64
       if: matrix.build == 'x86_64-pc-cygwin'
-      uses: ocaml-opam/cache@opam
+      uses: actions/cache@v4
       with:
         path: D:\Cache\cygwin\x86_64-pc-cygwin
         key: cygwin64-${{ needs.Analyse.outputs.cygwin }}
-        force-gzip: true
+        enableCrossOsArchive: true
     - name: src_ext/archives and opam-repository Cache
       id: archives
-      uses: ocaml-opam/cache@opam
+      uses: actions/cache@v4
       with:
         path: |
           src_ext/archives
           ~/opam-repository
         key: ${{ needs.Analyse.outputs.archives }}
-        force-gzip: true
+        enableCrossOsArchive: true
     - name: OCaml ${{ matrix.ocamlv }} Cache
       id: ocaml-cache
-      uses: ocaml-opam/cache@opam
+      uses: actions/cache@v4
       with:
         path: D:\Cache\ocaml-local.tar
         key: ${{ runner.os }}-${{ matrix.host }}-ocaml-${{ matrix.ocamlv }}-${{ needs.Analyse.outputs.ocaml-cache }}
-        force-gzip: true
+        enableCrossOsArchive: true
     - name: Unpack Cygwin
       shell: cmd
       run: .github\scripts\cygwin.cmd ${{ matrix.build }} D:\Cache\cygwin ${{ matrix.host }}
@@ -193,7 +193,7 @@ jobs:
       run: ldd ./opam.exe | test "$(grep -v -F /cygdrive/c/Windows/)" = ''
     - name: Upload opam binaries for Windows
       if: endsWith(matrix.host, '-pc-windows')
-      uses: actions/upload-artifact@v3
+      uses: actions/upload-artifact@v4
       with:
         name: opam-exe-${{ matrix.host }}-${{ matrix.ocamlv }}-${{ matrix.build }}
         path: |
@@ -233,16 +233,16 @@ jobs:
       uses: actions/checkout@v4
     - name: src_ext/archives and opam-repository Cache
       id: archives
-      uses: ocaml-opam/cache@opam
+      uses: actions/cache@v4
       with:
         path: |
           src_ext/archives
           ~/opam-repository
         key: ${{ needs.Analyse.outputs.archives }}
-        force-gzip: true
+        enableCrossOsArchive: true
     - name: OCaml ${{ matrix.ocamlv }} Cache
       id: ocaml-cache
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       with:
         path: ~/.cache/ocaml-local/**
         key: ${{ runner.os }}-ocaml-${{ matrix.ocamlv }}-${{ needs.Analyse.outputs.ocaml-cache }}
@@ -273,16 +273,16 @@ jobs:
       run: sudo apt install bubblewrap
     - name: src_ext/archives and opam-repository Cache
       id: archives
-      uses: ocaml-opam/cache@opam
+      uses: actions/cache@v4
       with:
         path: |
           src_ext/archives
           ~/opam-repository
         key: ${{ needs.Analyse.outputs.archives }}
-        force-gzip: true
+        enableCrossOsArchive: true
     - name: OCaml ${{ matrix.ocamlv }} Cache
       id: ocaml-cache
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       with:
         path: ~/.cache/ocaml-local/**
         key: ${{ runner.os }}-ocaml-${{ matrix.ocamlv }}-${{ needs.Analyse.outputs.ocaml-cache }}
@@ -291,7 +291,7 @@ jobs:
       run: bash -exu .github/scripts/main/ocaml-cache.sh ${{ runner.os }} ${{ matrix.ocamlv }}
     - name: opam bootstrap Cache
       id: opam-bootstrap
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       with:
         path: |
           ${{ env.OPAMBSROOT }}/**
@@ -302,7 +302,7 @@ jobs:
       run: bash -exu .github/scripts/main/opam-bs-cache.sh
     - name: opam-rt Cache
       id: opam-rt
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       with:
         path: ~/.cache/opam-rt/**
         key: ${{ runner.os }}-opam-rt-${{ matrix.ocamlv }}
@@ -327,16 +327,16 @@ jobs:
       uses: actions/checkout@v4
     - name: src_ext/archives and opam-repository Cache
       id: archives
-      uses: ocaml-opam/cache@opam
+      uses: actions/cache@v4
       with:
         path: |
           src_ext/archives
           ~/opam-repository
         key: ${{ needs.Analyse.outputs.archives }}
-        force-gzip: true
+        enableCrossOsArchive: true
     - name: OCaml ${{ matrix.ocamlv }} Cache
       id: ocaml-cache
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       with:
         path: ~/.cache/ocaml-local/**
         key: ${{ runner.os }}-ocaml-${{ matrix.ocamlv }}-${{ needs.Analyse.outputs.ocaml-cache }}
@@ -345,7 +345,7 @@ jobs:
       run: bash -exu .github/scripts/main/ocaml-cache.sh ${{ runner.os }} ${{ matrix.ocamlv }}
     - name: opam bootstrap Cache
       id: opam-bootstrap
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       with:
         path: |
           ${{ env.OPAMBSROOT }}/**
@@ -356,7 +356,7 @@ jobs:
       run: bash -exu .github/scripts/main/opam-bs-cache.sh
     - name: opam-rt Cache
       id: opam-rt
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       with:
         path: ~/.cache/opam-rt/**
         key: ${{ runner.os }}-opam-rt-${{ matrix.ocamlv }}
@@ -380,13 +380,13 @@ jobs:
       uses: actions/checkout@v4
     - name: src_ext/archives and opam-repository Cache
       id: archives
-      uses: ocaml-opam/cache@opam
+      uses: actions/cache@v4
       with:
         path: |
           src_ext/archives
           ~/opam-repository
         key: ${{ needs.Analyse.outputs.archives }}
-        force-gzip: true
+        enableCrossOsArchive: true
     - name: Cold
       run: |
         make compiler
@@ -415,16 +415,16 @@ jobs:
       uses: actions/checkout@v4
     - name: src_ext/archives and opam-repository Cache
       id: archives
-      uses: ocaml-opam/cache@opam
+      uses: actions/cache@v4
       with:
         path: |
           src_ext/archives
           ~/opam-repository
         key: ${{ needs.Analyse.outputs.archives }}
-        force-gzip: true
+        enableCrossOsArchive: true
     - name: OCaml ${{ matrix.ocamlv }} Cache
       id: ocaml-cache
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       with:
         path: ~/.cache/ocaml-local/**
         key: ${{ runner.os }}-ocaml-${{ matrix.ocamlv }}-${{ needs.Analyse.outputs.ocaml-cache }}
@@ -433,7 +433,7 @@ jobs:
       run: bash -exu .github/scripts/main/ocaml-cache.sh ${{ runner.os }} ${{ matrix.ocamlv }}
     - name: opam bootstrap Cache
       id: opam-bootstrap
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       with:
         path: |
           ${{ env.OPAMBSROOT }}/**
@@ -461,16 +461,16 @@ jobs:
       uses: actions/checkout@v4
     - name: src_ext/archives and opam-repository Cache
       id: archives
-      uses: ocaml-opam/cache@opam
+      uses: actions/cache@v4
       with:
         path: |
           src_ext/archives
           ~/opam-repository
         key: ${{ needs.Analyse.outputs.archives }}
-        force-gzip: true
+        enableCrossOsArchive: true
     - name: OCaml ${{ matrix.ocamlv }} Cache
       id: ocaml-cache
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       with:
         path: ~/.cache/ocaml-local/**
         key: ${{ runner.os }}-ocaml-${{ matrix.ocamlv }}-${{ needs.Analyse.outputs.ocaml-cache }}
@@ -479,7 +479,7 @@ jobs:
       run: bash -exu .github/scripts/main/ocaml-cache.sh ${{ runner.os }} ${{ matrix.ocamlv }}
     - name: opam bootstrap Cache
       id: opam-bootstrap
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       with:
         path: |
           ${{ env.OPAMBSROOT }}/**
@@ -507,13 +507,13 @@ jobs:
     - name: Checkout tree
       uses: actions/checkout@v4
     - name: opam 1.2 root Cache
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       with:
         path: ${{ env.OPAM12CACHE }}
         key: ${{ runner.os }}-opam1.2-root
     - name: OCaml ${{ matrix.ocamlv }} Cache
       id: ocaml-cache
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       with:
         path: ~/.cache/ocaml-local/**
         key: ${{ runner.os }}-ocaml-${{ matrix.ocamlv }}-${{ needs.Analyse.outputs.ocaml-cache }}
@@ -538,13 +538,13 @@ jobs:
     - name: Checkout tree
       uses: actions/checkout@v4
     - name: opam 1.2 root Cache
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       with:
         path: ${{ env.OPAM12CACHE }}
         key: ${{ runner.os }}-opam1.2-root
     - name: OCaml ${{ matrix.ocamlv }} Cache
       id: ocaml-cache
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       with:
         path: ~/.cache/ocaml-local/**
         key: ${{ runner.os }}-ocaml-${{ matrix.ocamlv }}-${{ needs.Analyse.outputs.ocaml-cache }}
@@ -571,13 +571,13 @@ jobs:
       uses: actions/checkout@v4
     - name: src_ext/archives and opam-repository Cache
       id: archives
-      uses: ocaml-opam/cache@opam
+      uses: actions/cache@v4
       with:
         path: |
           src_ext/archives
           ~/opam-repository
         key: ${{ needs.Analyse.outputs.archives }}
-        force-gzip: true
+        enableCrossOsArchive: true
     - name: Get changed files
       id: files
       uses: Ana06/get-changed-files@v2.2.0
diff --git a/master_changes.md b/master_changes.md
index 2a005c0d86f..3d0a0e96851 100644
--- a/master_changes.md
+++ b/master_changes.md
@@ -118,6 +118,10 @@ users)
   * Depexts: set version for conf packages to check [#6079 @rjbou]
   * Depexts: add package to test containing `os-version` in filter [#6079 @rjbou]
   * Depexts: fix opensuse job [#6079 @rjbou]
+  * Use actions/cache instead of our own fork ocaml-opam/cache [#6081 @rjbou]
+  * Update action cache to v4 [#6081 @rjbou]
+  * Update action checkout to v4 [#6081 @rjbou]
+  * Update action upload-artifact to v4 [#6081 @rjbou]
 
 ## Doc