diff --git a/backend/pashub_fetcher/core_files.py b/backend/pashub_fetcher/core_files.py
index 75981cb1..87a4044a 100644
--- a/backend/pashub_fetcher/core_files.py
+++ b/backend/pashub_fetcher/core_files.py
@@ -73,7 +73,17 @@ def core_file_for(
         return CoreFiles.MEDIUM_TERM_IMPROVEMENT_PLAN
     if evidence_category is None and "-OSM-" in filename and "DR-N-A" in filename:
         return CoreFiles.RETROFIT_DESIGN_DOC
-    raise NotImplementedError
+    _prefix_skip = {
+        CoreFiles.RETROFIT_DESIGN_DOC,
+        CoreFiles.IMPROVEMENT_OPTION_EVALUATION,
+        CoreFiles.MEDIUM_TERM_IMPROVEMENT_PLAN,
+    }
+    for core_file in CoreFiles:
+        if core_file in _prefix_skip:
+            continue
+        if filename.startswith(core_file.value):
+            return core_file
+    return None
 
 
 def infer_file_type(filename: str) -> Optional[str]: