diff --git a/.github/workflows/ci_cd.yml b/.github/workflows/ci_cd.yml
index 274d8946f4..61d8ac80c3 100644
--- a/.github/workflows/ci_cd.yml
+++ b/.github/workflows/ci_cd.yml
@@ -172,6 +172,16 @@ jobs:
           LICENSE_SERVER: ${{ secrets.LICENSE_SERVER }}
           IMAGE_NAME: "ghcr.io/ansys/acp${{ github.event.inputs.docker_image_suffix || ':latest' }}"
 
+      - name: "Unit testing (2024R2 server)"
+        if: matrix.python-version == env.MAIN_PYTHON_VERSION
+        working-directory: tests/unittests
+        run: |
+          docker pull $IMAGE_NAME
+          poetry run pytest -v --license-server=1055@$LICENSE_SERVER --no-server-log-files --docker-image=$IMAGE_NAME --cov=ansys.acp.core --cov-report=term --cov-report=xml --cov-report=html --cov-append
+        env:
+          LICENSE_SERVER: ${{ secrets.LICENSE_SERVER }}
+          IMAGE_NAME: "ghcr.io/ansys/acp:2024r2"
+
       - name: "Upload coverage report (HTML)"
         uses: actions/upload-artifact@v4
         if: matrix.python-version == env.MAIN_PYTHON_VERSION
diff --git a/src/ansys/acp/core/_tree_objects/base.py b/src/ansys/acp/core/_tree_objects/base.py
index 42c7afac8e..7f89e02d73 100644
--- a/src/ansys/acp/core/_tree_objects/base.py
+++ b/src/ansys/acp/core/_tree_objects/base.py
@@ -285,6 +285,9 @@ def clone(self: Self, *, unlink: bool = False) -> Self:
         new_object_info.properties.CopyFrom(self._pb_object.properties)
         if unlink:
             unlink_objects(new_object_info.properties)
+            # Since there may be links in the unknown fields, we need to
+            # discard them to avoid errors when storing the object.
+            new_object_info.properties.DiscardUnknownFields()  # type: ignore
         new_object_info.info.name = self._pb_object.info.name
         return type(self)._from_object_info(object_info=new_object_info)
 
diff --git a/tests/conftest.py b/tests/conftest.py
index 47183c3827..e09540c005 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -31,6 +31,7 @@
 
 import docker
 from hypothesis import settings
+from packaging.version import parse as parse_version
 import pytest
 
 from ansys.acp.core import (
@@ -260,3 +261,14 @@ def inner(model, relative_file_path="square_and_solid.stp"):
         )
 
     return inner
+
+
+@pytest.fixture
+def xfail_before(acp_instance):
+    """Mark a test as expected to fail before a certain server version."""
+
+    def inner(version: str):
+        if parse_version(acp_instance.server_version) < parse_version(version):
+            pytest.xfail(f"Expected to fail until server version {version!r}")
+
+    return inner
diff --git a/tests/unittests/test_model.py b/tests/unittests/test_model.py
index 70b3f7bbf2..d32bf6b368 100644
--- a/tests/unittests/test_model.py
+++ b/tests/unittests/test_model.py
@@ -251,11 +251,12 @@ def test_regression_454(minimal_complete_model):
     assert not hasattr(minimal_complete_model, "store")
 
 
-def test_modeling_ply_export(acp_instance, minimal_complete_model):
+def test_modeling_ply_export(acp_instance, minimal_complete_model, xfail_before):
     """
     Test that the 'export_modeling_ply_geometries' method produces a file.
     The contents of the file are not checked.
     """
+    xfail_before("25.1")
     out_filename = "modeling_ply_export.step"
 
     with tempfile.TemporaryDirectory() as tmp_dir: