diff --git a/src/pytmv1/model/common.py b/src/pytmv1/model/common.py
index 45fd04e..29435c9 100644
--- a/src/pytmv1/model/common.py
+++ b/src/pytmv1/model/common.py
@@ -5,7 +5,7 @@
 from pydantic import BaseModel as PydanticBaseModel
 from pydantic import ConfigDict, Field
 from pydantic import RootModel as PydanticRootModel
-from pydantic import model_validator
+from pydantic import field_validator, model_validator
 from pydantic.alias_generators import to_camel
 
 from .enum import (
@@ -131,17 +131,24 @@ class Endpoint(BaseConsumable):
     endpoint_name: Value
     mac_address: ValueList
     ip: ValueList
-    os_name: OperatingSystem
-    os_version: str
-    os_description: str
-    product_code: ProductCode
-    installed_product_codes: List[ProductCode]
+    os_name: Optional[OperatingSystem] = None
+    os_version: Optional[str] = None
+    os_description: Optional[str] = None
+    product_code: Optional[ProductCode] = None
+    installed_product_codes: List[ProductCode] = Field(default=[])
     componentUpdatePolicy: Optional[str] = None
     componentUpdateStatus: Optional[str] = None
     componentVersion: Optional[str] = None
     policyName: Optional[str] = None
     protectionManager: Optional[str] = None
 
+    @field_validator("os_name", "product_code", mode="before")
+    @classmethod
+    def allow_empty_enum_string(cls, value: Any) -> Union[Any, None]:
+        if value == "":
+            return None
+        return value
+
 
 class EmailActivity(BaseConsumable):
     mail_msg_subject: Optional[str] = None
diff --git a/src/pytmv1/model/enum.py b/src/pytmv1/model/enum.py
index 710a94c..85f4e3f 100644
--- a/src/pytmv1/model/enum.py
+++ b/src/pytmv1/model/enum.py
@@ -261,7 +261,6 @@ class ProductCode(str, Enum):
     SAO = "sao"
     SDS = "sds"
     XES = "xes"
-    NOT_FOUND = ""
 
 
 class Provenance(str, Enum):
diff --git a/tests/integration/test_search.py b/tests/integration/test_search.py
index 0d80f1c..cca3d19 100755
--- a/tests/integration/test_search.py
+++ b/tests/integration/test_search.py
@@ -72,3 +72,14 @@ def test_list_endpoint_data(client):
     assert result.response.items[0].componentUpdatePolicy == "N-2"
     assert result.response.items[0].componentUpdateStatus == "pause"
     assert result.response.items[0].componentVersion == "outdatedVersion"
+
+
+def test_list_endpoint_data_optional_fields(client):
+    result = client.endpoint.list_data(endpointName="optional_fields")
+    assert result.result_code == ResultCode.SUCCESS
+    assert isinstance(result.response, ListEndpointDataResp)
+    assert len(result.response.items) > 0
+    assert not result.response.items[0].product_code
+    assert not result.response.items[0].os_name
+    assert not result.response.items[0].os_version
+    assert not result.response.items[0].os_description