diff --git a/medcat-den/src/medcat_den/base.py b/medcat-den/src/medcat_den/base.py
index b864cd35b..34b0d3f39 100644
--- a/medcat-den/src/medcat_den/base.py
+++ b/medcat-den/src/medcat_den/base.py
@@ -1,6 +1,6 @@
 from typing import Optional
 
-from pydantic import BaseModel
+from pydantic import BaseModel, field_validator
 
 
 from medcat.cat import CAT
@@ -26,3 +26,19 @@ def from_model_pack(cls, cat: CAT) -> 'ModelInfo':
             model_card=mc,
             base_model=bm,
         )
+
+    @field_validator('model_card', mode='before')
+    @classmethod
+    def make_permissive(cls, v: dict) -> dict:
+        """Accept dict even if it's missing new optional fields"""
+        if isinstance(v, dict):
+            defaults = {
+                'Pipeline Description': {"core": {}, "addons": []},
+                'Required Plugins': [],
+            }
+            out_dict = {**defaults, **v}  # v overwrites defaults
+            if out_dict.get("Source Ontology") is None:
+                out_dict['Source Ontology'] = ['Unknown']
+            return out_dict
+        return v
+
diff --git a/medcat-den/tests/test_model_card_validity.py b/medcat-den/tests/test_model_card_validity.py
new file mode 100644
index 000000000..430d3215a
--- /dev/null
+++ b/medcat-den/tests/test_model_card_validity.py
@@ -0,0 +1,72 @@
+from medcat_den.base import ModelInfo
+
+
+MODEL_CARD_NO_NEW_KEYS = {
+    "Model ID": "0a1b2c3d4e",
+    "Source Ontology": [],
+    "Last Modified On": "2025-01-01",
+    "History (from least to most recent)": ["aa1122ee44"],
+    "Description": "Test model",
+    "Location": "test",
+    "MetaCAT models": [],
+    "Basic CDB Stats": {
+        "Number of concepts": 0,
+        "Number of names": 0,
+        "Number of concepts that received training": 0,
+        "Number of seen training examples in total": 0,
+        "Average training examples per concept": 0,
+        "Unsupervised training history": [],
+        "Supervised training history": [],
+    },
+    "Performance": {},
+    "Important Parameters (Partial view, all available in cat.config)": {},
+    "MedCAT Version": "2.0.0",
+}
+
+NEW_KV = {
+    "Pipeline Description": {
+        "core": {}, "addons": []
+    },
+    "Required Plugins": []
+}
+
+
+MODEL_CARD_WITH_NEW_KEYS = {
+    **MODEL_CARD_NO_NEW_KEYS,
+    **NEW_KV
+}
+
+
+def test_validates_with_old_format():
+    model = ModelInfo(
+        model_id="test_id",
+        model_card=MODEL_CARD_NO_NEW_KEYS,
+            base_model=None,
+        model_name="test_model",
+        model_num=1,
+    )
+    assert isinstance(model, ModelInfo)
+
+
+def test_validates_with_new_format():
+    model = ModelInfo(
+        model_id="test_id",
+        model_card=MODEL_CARD_WITH_NEW_KEYS,
+            base_model=None,
+        model_name="test_model",
+        model_num=1,
+    )
+    assert isinstance(model, ModelInfo)
+
+
+def test_new_format_keeps_values():
+    model = ModelInfo(
+        model_id="test_id",
+        model_card=MODEL_CARD_WITH_NEW_KEYS,
+            base_model=None,
+        model_name="test_model",
+        model_num=1,
+    )
+    mc = model.model_card
+    for key, exp_value in NEW_KV.items():
+        assert exp_value == mc[key]