diff --git a/modules/core/src/main/java/com/bytedesk/core/message/MessageExtra.java b/modules/core/src/main/java/com/bytedesk/core/message/MessageExtra.java
index 2ba654a436..a785663d6b 100644
--- a/modules/core/src/main/java/com/bytedesk/core/message/MessageExtra.java
+++ b/modules/core/src/main/java/com/bytedesk/core/message/MessageExtra.java
@@ -42,6 +42,10 @@ public class MessageExtra extends BaseExtra {
     
     private String orgUid; // 组织UID
 
+    // Thread会话内消息排序序号，服务端分配的自增值
+    @Builder.Default
+    private Long sequenceNumber = 1L;
+
     public static MessageExtra fromJson(String json) {
         MessageExtra result = BaseExtra.fromJson(json, MessageExtra.class);
         return result != null ? result : MessageExtra.builder().build();