diff --git a/unittests/test_apiutils.py b/unittests/test_apiutils.py
index 2c62d3e03e007ac131db7f36de046924e8f1949b..fdd5adda065a563b15008f1b840539c110921b65 100644
--- a/unittests/test_apiutils.py
+++ b/unittests/test_apiutils.py
@@ -965,22 +965,22 @@ def test_describe_diff():
     diff = compare_entities(recA, recB)
     diffout = describe_diff(*diff)
 
-    assert diffout.startswith("## Difference between the old version and the new version of None")
+    assert diffout.startswith("## Difference between the first version and the second version of None")
 
     # The output of the describe_diff function is currently not ordered (e.g. by name of the property)
     # so we cannot just compare a well-defined output string.
 
-    assert "it does not exist in the old version:" in diffout
-    assert "old version: {'value': 2}" in diffout
-    assert "new version: {'value': 12}" in diffout
+    assert "it does not exist in the first version:" in diffout
+    assert "first version: {'value': 2}" in diffout
+    assert "second version: {'value': 12}" in diffout
 
-    assert "old version: {'unit': 'K'}" in diffout
-    assert "new version: {'unit': '°C'}" in diffout
+    assert "first version: {'unit': 'K'}" in diffout
+    assert "second version: {'unit': '°C'}" in diffout
 
     diffout = describe_diff(*diff, name="Entity")
-    assert diffout.startswith("## Difference between the old version and the new version of Entity")
+    assert diffout.startswith("## Difference between the first version and the second version of Entity")
 
-    diffout = describe_diff(*diff, label_old="recA", label_new="recB")
+    diffout = describe_diff(*diff, label_e0="recA", label_e1="recB")
     assert "recA: {'value': 2}" in diffout
     assert "recB: {'value': 12}" in diffout
 
@@ -989,5 +989,5 @@ def test_describe_diff():
 
     assert "it does not exist in the recA:" in diffout
 
-    assert "old" not in diffout
-    assert "new" not in diffout
+    assert "first" not in diffout
+    assert "second" not in diffout