diff --git a/src/App.js b/src/App.js
index 69ac7a8..934e96f 100644
--- a/src/App.js
+++ b/src/App.js
@@ -9,6 +9,16 @@ import {load_config,bgimg_style} from './Config';
 import ImasuguApp from './imasugu/src/App';
 
 function DeprecatedAlert(props) {
+    if(document.domain==='hole.xmcp.ml')
+        return (
+            <div className="flow-item">
+                <div className="box box-tip">
+                    <p><b>请使用新域名访问P大树洞！</b></p>
+                    <p><a href="http://pkuhelper.pku.edu.cn/hole/">pkuhelper.pku.edu.cn/hole</a></p>
+                    <p>当前域名将停止支持</p>
+                </div>
+            </div>
+        );
     return null;
 }
 
diff --git a/src/Message.js b/src/Message.js
new file mode 100644
index 0000000..2ea98f8
--- /dev/null
+++ b/src/Message.js
@@ -0,0 +1,65 @@
+import React, {Component, PureComponent} from 'react';
+import {PKUHELPER_ROOT,get_json} from './flows_api';
+import {Time} from './Common';
+
+export class MessageViewer extends PureComponent {
+    constructor(props) {
+        super(props);
+        this.state={
+            loading_status: 'idle',
+            msg: [],
+        };
+    }
+
+    componentDidMount() {
+        this.load();
+    }
+
+    load() {
+        if(this.state.loading_status==='loading') return;
+        this.setState({
+            loading_status: 'loading',
+        },()=>{
+            fetch(PKUHELPER_ROOT+'api_xmcp/hole/system_msg?user_token='+encodeURIComponent(this.props.token))
+                .then(get_json)
+                .then((json)=>{
+                    if(json.error)
+                        throw new Error(json.error);
+                    else
+                        this.setState({
+                            loading_status: 'done',
+                            msg: json.result,
+                        });
+                })
+                .catch((err)=>{
+                    console.error(err);
+                    alert(''+err);
+                    this.setState({
+                        loading_status: 'failed',
+                    });
+                })
+
+        });
+    }
+
+    render() {
+        if(this.state.loading_status==='loading')
+            return (<p className="box box-tip">加载中……</p>);
+        else if(this.state.loading_status==='failed')
+            return (<div className="box box-tip"><a onClick={()=>{this.load()}}>重新加载</a></div>);
+        else if(this.state.loading_status==='done')
+            return this.state.msg.map((msg)=>(
+                <div className="box">
+                    <div className="box-header">
+                        <Time stamp={msg.timestamp} />
+                        &nbsp; <b>{msg.title}</b>
+                    </div>
+                    <div className="box-content">
+                        <pre>{msg.content}</pre>
+                    </div>
+                </div>
+            ));
+        else
+            return null;
+    }
+}
\ No newline at end of file
diff --git a/src/Title.js b/src/Title.js
index ff5d3da..3723167 100644
--- a/src/Title.js
+++ b/src/Title.js
@@ -116,7 +116,7 @@ class ControlBar extends PureComponent {
                             'P大树洞 网页版',
                             <div>
                                 <PromotionBar />
-                                <LoginForm />
+                                <LoginForm show_sidebar={this.props.show_sidebar} />
                                 <div className="box list-menu">
                                     <a onClick={()=>{this.props.show_sidebar(
                                         '设置',
diff --git a/src/UserAction.js b/src/UserAction.js
index af15737..5d5efe4 100644
--- a/src/UserAction.js
+++ b/src/UserAction.js
@@ -1,12 +1,13 @@
 import React, {Component, PureComponent} from 'react';
 import copy from 'copy-to-clipboard';
 import {SafeTextarea} from './Common';
-import {API_VERSION_PARAM,PKUHELPER_ROOT,API} from './flows_api'
+import {API_VERSION_PARAM,PKUHELPER_ROOT,API,get_json} from './flows_api'
 import md5 from 'md5';
 
 import './UserAction.css';
 
 import {API_BASE} from './Common';
+import {MessageViewer} from './Message';
 const LOGIN_BASE=PKUHELPER_ROOT+'services/login';
 const MAX_IMG_PX=2500;
 const MAX_IMG_FILESIZE=300000;
@@ -68,15 +69,16 @@ export class LoginForm extends Component {
                 },
                 body: data,
             })
-                .then((res)=>res.json())
+                .then(get_json)
                 .then((json)=>{
                     if(json.code!==0) {
                         if(json.msg) alert(json.msg);
                         throw new Error(JSON.stringify(json));
                     }
 
+                    let freshman_welcome=json.uid.indexOf('19')===0 && (+new Date())<1567958400000; // 2019-09-09 0:00 GMT+8
                     set_token(json.user_token);
-                    alert(`成功以 ${json.name} 的身份登录`);
+                    alert(`成功以 ${json.name} 的身份登录`+(freshman_welcome ? '\n欢迎来到北京大学！' : ''));
                     this.setState({
                         loading_status: 'done',
                     });
@@ -131,6 +133,13 @@ export class LoginForm extends Component {
                                 <b>您已登录。</b>
                                 <button type="button" onClick={()=>{token.set_value(null);}}>注销</button>
                             </p>
+                            <p>
+                                <a onClick={()=>{this.props.show_sidebar(
+                                    '系统消息',
+                                    <MessageViewer token={token.value} />
+                                )}}>查看系统消息</a><br />
+                                当您发送的内容违规时，我们将用系统消息提示您
+                            </p>
                             <p>
                                 <a onClick={this.copy_token.bind(this,token.value)}>复制 User Token</a><br />
                                 User Token 可用于迁移登录状态，请勿泄露，因为它与您的账户唯一对应且泄露后无法重置
@@ -222,7 +231,7 @@ export class ReplyForm extends Component {
             },
             body: data,
         })
-            .then((res)=>res.json())
+            .then(get_json)
             .then((json)=>{
                 if(json.code!==0) {
                     if(json.msg) alert(json.msg);
@@ -248,7 +257,7 @@ export class ReplyForm extends Component {
     render() {
         return (
             <form onSubmit={this.on_submit.bind(this)} className={'reply-form box'+(this.state.text?' reply-sticky':'')}>
-                <SafeTextarea ref={this.area_ref} id={this.props.pid} on_change={this.on_change_bound} on_submit={this.on_submit.bind(this)} />
+                <SafeTextarea key={this.props.pid} ref={this.area_ref} id={this.props.pid} on_change={this.on_change_bound} on_submit={this.on_submit.bind(this)} />
                 {this.state.loading_status==='loading' ?
                     <button disabled="disabled">
                         <span className="icon icon-loading" />
@@ -302,7 +311,7 @@ export class PostForm extends Component {
             },
             body: data,
         })
-            .then((res)=>res.json())
+            .then(get_json)
             .then((json)=>{
                 if(json.code!==0) {
                     if(json.msg) alert(json.msg);
diff --git a/src/flows_api.js b/src/flows_api.js
index acd7f6f..7f6d463 100644
--- a/src/flows_api.js
+++ b/src/flows_api.js
@@ -1,13 +1,17 @@
 import {API_BASE} from './Common';
 
 export const API_VERSION_PARAM='&PKUHelperAPI=3.0';
-export const PKUHELPER_ROOT= // don't use :10301 if we are already in the same domain
-    document.domain==='pkuhelper.pku.edu.cn' ? '/' : '//pkuhelper.pku.edu.cn/';
+export const PKUHELPER_ROOT='//pkuhelper.pku.edu.cn/';
 
 function token_param(token) {
     return API_VERSION_PARAM + (token ? ('&user_token='+token) : '');
 }
 
+export function get_json(res) {
+    if(!res.ok) throw Error(`网络错误 ${res.status} ${res.statusText}`);
+    return res.json();
+}
+
 export const API={
     load_replies: (pid,token,color_picker)=>{
         return fetch(
@@ -15,7 +19,7 @@ export const API={
             '&pid='+pid+
             token_param(token)
         )
-            .then((res)=>res.json())
+            .then(get_json)
             .then((json)=>{
                 if(json.code!==0) {
                     if(json.msg) throw new Error(json.msg);
@@ -48,7 +52,7 @@ export const API={
             },
             body: data,
         })
-            .then((res)=>res.json())
+            .then(get_json)
             .then((json)=>{
                 if(json.code!==0) {
                     if(json.msg && json.msg==='已经关注过辣') {}
@@ -73,7 +77,7 @@ export const API={
             },
             body: data,
         })
-            .then((res)=>res.json())
+            .then(get_json)
             .then((json)=>{
                 if(json.code!==0) {
                     if(json.msg) alert(json.msg);
@@ -89,7 +93,7 @@ export const API={
             '&p='+page+
             token_param(token)
         )
-            .then((res)=>res.json())
+            .then(get_json)
             .then((json)=>{
                 if(json.code!==0)
                     throw new Error(JSON.stringify(json));
@@ -104,7 +108,7 @@ export const API={
             '&keywords='+encodeURIComponent(keyword)+
             token_param(token)
         )
-            .then((res)=>res.json())
+            .then(get_json)
             .then((json)=>{
                 if(json.code!==0) {
                     if(json.msg) alert(json.msg);
@@ -120,7 +124,7 @@ export const API={
             '&pid='+pid+
             token_param(token)
         )
-            .then((res)=>res.json())
+            .then(get_json)
             .then((json)=>{
                 if(json.code!==0) {
                     if(json.msg) throw new Error(json.msg);
@@ -135,7 +139,7 @@ export const API={
             API_BASE+'/api.php?action=getattention'+
             token_param(token)
         )
-            .then((res)=>res.json())
+            .then(get_json)
             .then((json)=>{
                 if(json.code!==0) {
                     if(json.msg) alert(json.msg);