diff --git a/.actions/assistant.py b/.actions/assistant.py
index 7b2d49423d622..0109a988d5692 100644
--- a/.actions/assistant.py
+++ b/.actions/assistant.py
@@ -368,20 +368,6 @@ def _prune_packages(req_file: str, packages: Sequence[str]) -> None:
         print(final)
         path.write_text("\n".join(final) + "\n")
 
-    @staticmethod
-    def _replace_min(fname: str) -> None:
-        with open(fname, encoding="utf-8") as fopen:
-            req = fopen.read().replace(">=", "==")
-        with open(fname, "w", encoding="utf-8") as fwrite:
-            fwrite.write(req)
-
-    @staticmethod
-    def replace_oldest_ver(requirement_fnames: Sequence[str] = REQUIREMENT_FILES_ALL) -> None:
-        """Replace the min package version by fixed one."""
-        for fname in requirement_fnames:
-            print(fname)
-            AssistantCLI._replace_min(fname)
-
     @staticmethod
     def copy_replace_imports(
         source_dir: str,
diff --git a/.azure/gpu-tests-fabric.yml b/.azure/gpu-tests-fabric.yml
index c2d492e5b9564..f506aa2008df9 100644
--- a/.azure/gpu-tests-fabric.yml
+++ b/.azure/gpu-tests-fabric.yml
@@ -99,7 +99,9 @@ jobs:
         displayName: "Image info & NVIDIA"
 
       - bash: |
-          python .actions/assistant.py replace_oldest_ver
+          cd requirements/fabric
+          pip install -U "lightning-utilities[cli]"
+          python -m lightning_utilities.cli requirements set-oldest --req_files "['base.txt', 'strategies.txt']"
           pip install "cython<3.0" wheel  # for compatibility
         condition: contains(variables['Agent.JobName'], 'oldest')
         displayName: "setting oldest dependencies"
diff --git a/.azure/gpu-tests-pytorch.yml b/.azure/gpu-tests-pytorch.yml
index 16ced045ddade..68e99f2f6285a 100644
--- a/.azure/gpu-tests-pytorch.yml
+++ b/.azure/gpu-tests-pytorch.yml
@@ -103,7 +103,9 @@ jobs:
         displayName: "Image info & NVIDIA"
 
       - bash: |
-          python .actions/assistant.py replace_oldest_ver
+          cd requirements/pytorch
+          pip install -U "lightning-utilities[cli]"
+          python -m lightning_utilities.cli requirements set-oldest --req_files "['base.txt', 'extra.txt', 'strategies.txt', 'examples.txt']"
           pip install "cython<3.0" wheel  # for compatibility
         condition: contains(variables['Agent.JobName'], 'oldest')
         displayName: "setting oldest dependencies"
diff --git a/.github/workflows/ci-tests-fabric.yml b/.github/workflows/ci-tests-fabric.yml
index ed2301d878a10..888de9bdb4a09 100644
--- a/.github/workflows/ci-tests-fabric.yml
+++ b/.github/workflows/ci-tests-fabric.yml
@@ -94,7 +94,9 @@ jobs:
       - name: Set min. dependencies
         if: ${{ matrix.requires == 'oldest' }}
         run: |
-          python .actions/assistant.py replace_oldest_ver
+          cd requirements/fabric
+          pip install -U "lightning-utilities[cli]"
+          python -m lightning_utilities.cli requirements set-oldest --req_files "['base.txt', 'strategies.txt']"
           pip install "cython<3.0" wheel
           pip install "pyyaml==5.4" --no-build-isolation
 
diff --git a/.github/workflows/ci-tests-pytorch.yml b/.github/workflows/ci-tests-pytorch.yml
index 49ff08df2eab1..e527961590c3a 100644
--- a/.github/workflows/ci-tests-pytorch.yml
+++ b/.github/workflows/ci-tests-pytorch.yml
@@ -99,7 +99,9 @@ jobs:
       - name: Set min. dependencies
         if: ${{ matrix.requires == 'oldest' }}
         run: |
-          python .actions/assistant.py replace_oldest_ver
+          cd requirements/pytorch
+          pip install -U "lightning-utilities[cli]"
+          python -m lightning_utilities.cli requirements set-oldest --req_files "['base.txt', 'extra.txt', 'strategies.txt', 'examples.txt']"
           pip install "cython<3.0" wheel
           pip install "pyyaml==5.4" --no-build-isolation
 
diff --git a/.lightning/workflows/fabric.yml b/.lightning/workflows/fabric.yml
index 265de22b714fb..438f56ef7fe94 100644
--- a/.lightning/workflows/fabric.yml
+++ b/.lightning/workflows/fabric.yml
@@ -43,7 +43,10 @@ run: |
 
   if [ "${TORCH_VER}" == "2.1" ]; then
     echo "Set oldest versions"
-    python .actions/assistant.py replace_oldest_ver
+    cd requirements/fabric
+    pip install -U "lightning-utilities[cli]"
+    python -m lightning_utilities.cli requirements set-oldest --req_files "['base.txt', 'strategies.txt']"
+    cd ../..
     pip install "cython<3.0" wheel  # for compatibility
   fi
 
diff --git a/.lightning/workflows/pytorch.yml b/.lightning/workflows/pytorch.yml
index b87ab98a8c0cd..5c92bf881d969 100644
--- a/.lightning/workflows/pytorch.yml
+++ b/.lightning/workflows/pytorch.yml
@@ -43,7 +43,10 @@ run: |
 
   if [ "${TORCH_VER}" == "2.1" ]; then
     recho "Set oldest versions"
-    python .actions/assistant.py replace_oldest_ver
+    cd requirements/pytorch
+    pip install -U "lightning-utilities[cli]"
+    python -m lightning_utilities.cli requirements set-oldest --req_files "['base.txt', 'extra.txt', 'strategies.txt', 'examples.txt']"
+    cd ../..
     pip install "cython<3.0" wheel  # for compatibility
   fi