diff --git a/deploy/convert_server.py b/deploy/convert_server.py
index f5515ca..bfc6520 100755
--- a/deploy/convert_server.py
+++ b/deploy/convert_server.py
@@ -163,7 +163,11 @@ class Handler(BaseHTTPRequestHandler):
         doc_id = parsed.path.split("/")[-1]
         supps = query("SELECT id, contract_id FROM supplements WHERE document_id = %s", (doc_id,))
         for s in (supps or []):
-            execute("DELETE FROM spec_current WHERE contract_id = %s", (s["contract_id"],))
+            execute(
+                """DELETE FROM spec_current WHERE contract_id = %s
+                   AND last_event_id IN (SELECT id FROM spec_events WHERE supplement_id = %s)""",
+                (s["contract_id"], s["id"]),
+            )
             execute("DELETE FROM spec_events WHERE supplement_id = %s", (s["id"],))
             execute("DELETE FROM supplements WHERE id = %s", (s["id"],))
         execute("DELETE FROM documents WHERE id = %s", (doc_id,))
@@ -177,6 +181,10 @@ class Handler(BaseHTTPRequestHandler):
         length = int(self.headers.get("Content-Length", 0))
         body = json.loads(self.rfile.read(length)) if length > 0 else {}
         keep_ids = set(body.get("keep_ids", []))
+        # Prevent DoS: too many IDs
+        if len(keep_ids) > 1000:
+            self._json({"ok": False, "error": "too many keep_ids (max 1000)"}, 400)
+            return
         docs = query("SELECT id FROM documents", ())
         deleted = 0
         for d in (docs or []):
@@ -184,7 +192,11 @@ class Handler(BaseHTTPRequestHandler):
                 continue
             supps = query("SELECT id, contract_id FROM supplements WHERE document_id = %s", (d["id"],))
             for s in (supps or []):
-                execute("DELETE FROM spec_current WHERE contract_id = %s", (s["contract_id"],))
+                execute(
+                    """DELETE FROM spec_current WHERE contract_id = %s
+                       AND last_event_id IN (SELECT id FROM spec_events WHERE supplement_id = %s)""",
+                    (s["contract_id"], s["id"]),
+                )
                 execute("DELETE FROM spec_events WHERE supplement_id = %s", (s["id"],))
                 execute("DELETE FROM supplements WHERE id = %s", (s["id"],))
             execute("DELETE FROM documents WHERE id = %s", (d["id"],))
diff --git a/deploy/db/supplements.py b/deploy/db/supplements.py
index 33652b1..41fa40e 100644
--- a/deploy/db/supplements.py
+++ b/deploy/db/supplements.py
@@ -28,25 +28,31 @@ def get(supp_id):
 
 
 def delete_by_document(contract_id, filename):
-    """Delete supplement+document by contract+filename (cascade: spec_events first)."""
-    row = query(
+    """Delete ALL supplements+documents by contract+filename (cascade: spec_events first).
+    Handles duplicates from previously failed uploads."""
+    rows = query(
         """SELECT s.id as sid, s.document_id FROM supplements s
            JOIN documents d ON d.id = s.document_id
            WHERE s.contract_id = %s AND d.filename = %s""",
         (contract_id, filename),
     )
-    if row:
-        r = row[0]
-        # 1. Delete spec_current for this contract (FK to spec_events)
-        execute("DELETE FROM spec_current WHERE contract_id = %s", (contract_id,))
+    if not rows:
+        return False
+
+    for r in rows:
+        # 1. Delete spec_current rows referencing this supplement's events
+        execute(
+            """DELETE FROM spec_current WHERE contract_id = %s
+               AND last_event_id IN (SELECT id FROM spec_events WHERE supplement_id = %s)""",
+            (contract_id, r["sid"]),
+        )
         # 2. Delete spec_events referencing this supplement
         execute("DELETE FROM spec_events WHERE supplement_id = %s", (r["sid"],))
         # 3. Delete supplement
         execute("DELETE FROM supplements WHERE id = %s", (r["sid"],))
         # 4. Delete document
         execute("DELETE FROM documents WHERE id = %s", (r["document_id"],))
-        return True
-    return False
+    return True
 
 
 def delete(supp_id):