diff --git a/apps/api/src/services/telegram_gateway.py b/apps/api/src/services/telegram_gateway.py
index a79fbc78..fcddcc69 100644
--- a/apps/api/src/services/telegram_gateway.py
+++ b/apps/api/src/services/telegram_gateway.py
@@ -2593,8 +2593,13 @@ class TelegramGateway:
             "text": text[:4096],
             "parse_mode": parse_mode,
         }
+        # 2026-04-03 ogt: supergroup 跨 Bot reply 需用 reply_parameters (Bot API v6.7+)
+        # 舊的 reply_to_message_id 在 supergroup 會 400，改用新格式 + allow_sending_without_reply
         if reply_to_message_id:
-            payload["reply_to_message_id"] = reply_to_message_id
+            payload["reply_parameters"] = {
+                "message_id": reply_to_message_id,
+                "allow_sending_without_reply": True,
+            }
 
         response = await self._http_client.post(url, json=payload)
         response.raise_for_status()