diff --git a/src/citrine/__version__.py b/src/citrine/__version__.py
index f5752882d..0419a93d2 100644
--- a/src/citrine/__version__.py
+++ b/src/citrine/__version__.py
@@ -1 +1 @@
-__version__ = "5.3.0"
+__version__ = "5.3.1"
diff --git a/src/citrine/resources/ingestion.py b/src/citrine/resources/ingestion.py
index 08ce0d994..4404d0b1c 100644
--- a/src/citrine/resources/ingestion.py
+++ b/src/citrine/resources/ingestion.py
@@ -74,11 +74,18 @@ class IngestionErrorLevel(BaseEnumeration):
     INFO = "info"
 
 
+class _IngestionErrorTypeProperty(properties.Enumeration):
+    """Maps error types this SDK doesn't know yet to UNKNOWN_ERROR, so the trace's msg survives."""
+
+    def _deserialize(self, value: str) -> IngestionErrorType:
+        return IngestionErrorType.from_str(value) or IngestionErrorType.UNKNOWN_ERROR
+
+
 class IngestionErrorTrace(Resource["IngestionErrorTrace"]):
     """[ALPHA] Detailed information about an ingestion issue."""
 
     family = properties.Enumeration(IngestionErrorFamily, "family")
-    error_type = properties.Enumeration(IngestionErrorType, "error_type")
+    error_type = _IngestionErrorTypeProperty(IngestionErrorType, "error_type")
     level = properties.Enumeration(IngestionErrorLevel, "level")
     msg = properties.String("msg")
     dataset_file_id = properties.Optional(properties.UUID(), "dataset_file_id", default=None)
diff --git a/tests/resources/test_ingestion.py b/tests/resources/test_ingestion.py
index 7fede465b..85798fbae 100644
--- a/tests/resources/test_ingestion.py
+++ b/tests/resources/test_ingestion.py
@@ -396,3 +396,20 @@ def test_status_parses_server_error_types(error_type):
         )
     )
     assert status.errors[0].error_type == IngestionErrorType(error_type)
+
+
+def test_status_falls_back_on_unknown_error_type():
+    status = IngestionStatus.build(
+        IngestionStatusResponseDataFactory(
+            errors=[
+                {
+                    "family": "data",
+                    "error_type": "some_future_error",
+                    "level": "error",
+                    "msg": "A server-only ingestion error",
+                }
+            ]
+        )
+    )
+    assert status.errors[0].error_type == IngestionErrorType.UNKNOWN_ERROR
+    assert status.errors[0].msg == "A server-only ingestion error"