diff --git a/frontend/src/components/main-side-nav-folded.js b/frontend/src/components/main-side-nav-folded.js
index 6213baa507..5d9f66e4ea 100644
--- a/frontend/src/components/main-side-nav-folded.js
+++ b/frontend/src/components/main-side-nav-folded.js
@@ -3,7 +3,7 @@ import PropTypes from 'prop-types';
 import ModalPortal from './modal-portal';
 import { Link } from '@gatsbyjs/reach-router';
 import { gettext, siteRoot, canInvitePeople, enableTC, sideNavFooterCustomHtml, showWechatSupportGroup,
-  isDocs, isPro, isDBSqlite3, customNavItems, mediaUrl, curNoteMsg, enableShowAbout } from '../utils/constants';
+  isPro, isDBSqlite3, customNavItems, mediaUrl, curNoteMsg, enableShowAbout } from '../utils/constants';
 import { SIDE_PANEL_FOLDED_WIDTH, SUB_NAV_ITEM_HEIGHT } from '../constants';
 import Tip from './side-nav-icon-tip';
 import FilesSubNav from '../components/files-sub-nav';
@@ -110,7 +110,7 @@ class MainSideNavFolded extends React.Component {
   };
 
   render() {
-    let showActivity = isDocs || isPro || !isDBSqlite3;
+    let showActivity = isPro || !isDBSqlite3;
     const { groupItems, isFilesSubNavShown } = this.state;
     return (
       <Fragment>
diff --git a/frontend/src/components/main-side-nav.js b/frontend/src/components/main-side-nav.js
index 3a38f2c3b3..57aebaa852 100644
--- a/frontend/src/components/main-side-nav.js
+++ b/frontend/src/components/main-side-nav.js
@@ -6,7 +6,7 @@ import {
   gettext, siteRoot, canAddGroup, canAddRepo, canShareRepo,
   canGenerateShareLink, canGenerateUploadLink, canInvitePeople,
   enableTC, sideNavFooterCustomHtml, enableShowAbout, showWechatSupportGroup,
-  canViewOrg, isDocs, isPro, isDBSqlite3, customNavItems, mediaUrl
+  canViewOrg, isPro, isDBSqlite3, customNavItems, mediaUrl
 } from '../utils/constants';
 import { seafileAPI } from '../utils/seafile-api';
 import { Utils } from '../utils/utils';
@@ -224,7 +224,7 @@ class MainSideNav extends React.Component {
   };
 
   render() {
-    let showActivity = isDocs || isPro || !isDBSqlite3;
+    let showActivity = isPro || !isDBSqlite3;
     const { filesNavUnfolded, groupItems } = this.state;
     return (
       <Fragment>
diff --git a/frontend/src/pages/lib-content-view/lib-content-view.js b/frontend/src/pages/lib-content-view/lib-content-view.js
index b410f4878f..ba90c75833 100644
--- a/frontend/src/pages/lib-content-view/lib-content-view.js
+++ b/frontend/src/pages/lib-content-view/lib-content-view.js
@@ -10,7 +10,6 @@ import { navigate } from '@gatsbyjs/reach-router';
 import { gettext, siteRoot, username } from '../../utils/constants';
 import { seafileAPI } from '../../utils/seafile-api';
 import { Utils } from '../../utils/utils';
-import collabServer from '../../utils/collab-server';
 import { Dirent, FileTag, RepoTag, RepoInfo } from '../../models';
 import TreeNode from '../../components/tree-view/tree-node';
 import treeHelper from '../../components/tree-view/tree-helper';
@@ -254,7 +253,6 @@ class LibContentView extends React.Component {
 
   componentWillUnmount() {
     window.onpopstate = this.oldonpopstate;
-    collabServer.unwatchRepo(this.props.repoID, this.onRepoUpdateEvent);
     this.unsubscribeEvent();
     this.unsubscribeEventBus && this.unsubscribeEventBus();
     this.props.eventBus.dispatch(EVENT_BUS_TYPE.CURRENT_LIBRARY_CHANGED, {
@@ -393,11 +391,6 @@ class LibContentView extends React.Component {
 
   // load data
   loadDirData = (path) => {
-    let repoID = this.props.repoID;
-
-    // listen current repo
-    collabServer.watchRepo(repoID, this.onRepoUpdateEvent);
-
     // list used FileTags
     this.updateUsedRepoTags();
 
diff --git a/frontend/src/pages/markdown-editor/header-toolbar/header-toolbar.js b/frontend/src/pages/markdown-editor/header-toolbar/header-toolbar.js
index 7f23efd285..a534a7dd47 100644
--- a/frontend/src/pages/markdown-editor/header-toolbar/header-toolbar.js
+++ b/frontend/src/pages/markdown-editor/header-toolbar/header-toolbar.js
@@ -4,7 +4,6 @@ import { EXTERNAL_EVENTS, EventBus } from '@seafile/seafile-editor';
 import { gettext, canGenerateShareLink, isPro, mediaUrl, canLockUnlockFile } from '../../../utils/constants';
 import ButtonGroup from './button-group';
 import ButtonItem from './button-item';
-import CollabUsersButton from './collab-users-button';
 import MoreMenu from './more-menu';
 import FileInfo from './file-info';
 import Icon from '../../../components/icon';
@@ -16,7 +15,6 @@ import Dirent from '../../../../src/models/dirent';
 
 import '../css/header-toolbar.css';
 
-const { seafileCollabServer } = window.app.config;
 const { canDownloadFile, repoID, filePath, isRepoAdmin } = window.app.pageOptions;
 
 const propTypes = {
@@ -140,13 +138,6 @@ class HeaderToolbar extends React.Component {
               isStarred={this.props.fileInfo.isStarred}
             />
             <div className="topbar-btn-container">
-              {(seafileCollabServer && this.props.collabUsers.length > 0) &&
-                <CollabUsersButton
-                  className="collab-users-dropdown"
-                  users={this.props.collabUsers}
-                  id="usersButton"
-                />
-              }
               <ButtonGroup>
                 {(canLockUnlockFile && !isLocked) && (
                   <ButtonItem
@@ -268,13 +259,6 @@ class HeaderToolbar extends React.Component {
             <FileInfo toggleStar={this.props.toggleStar} editorApi={this.props.editorApi}
               fileInfo={this.props.fileInfo}/>
             <div className="topbar-btn-container">
-              {(seafileCollabServer && this.props.collabUsers.length > 0) &&
-                <CollabUsersButton
-                  className="collab-users-dropdown"
-                  users={this.props.collabUsers}
-                  id="usersButton"
-                />
-              }
               <ButtonGroup>
                 {saving ?
                   <button type={'button'} className={'btn btn-icon btn-secondary btn-active'}>
diff --git a/frontend/src/pages/markdown-editor/index.js b/frontend/src/pages/markdown-editor/index.js
index dc85f84d81..805ba67029 100644
--- a/frontend/src/pages/markdown-editor/index.js
+++ b/frontend/src/pages/markdown-editor/index.js
@@ -1,5 +1,4 @@
 import React, { Fragment } from 'react';
-import io from 'socket.io-client';
 import {
   EXTERNAL_EVENTS,
   EventBus,
@@ -22,7 +21,7 @@ const CryptoJS = require('crypto-js');
 const URL = require('url-parse');
 
 const { repoID, filePath, fileName, isLocked, lockedByMe } = window.app.pageOptions;
-const { siteRoot, serviceUrl, seafileCollabServer } = window.app.config;
+const { siteRoot, serviceUrl } = window.app.config;
 const userInfo = window.app.userInfo;
 const IMAGE_SUFFIXES = ['png', 'PNG', 'jpg', 'JPG', 'jpeg', 'JPEG', 'gif', 'GIF'];
 
@@ -46,7 +45,6 @@ class MarkdownEditor extends React.Component {
         id: '',
       },
       editorMode: 'rich',
-      collabServer: seafileCollabServer ? seafileCollabServer : null,
       showMarkdownEditorDialog: false,
       showShareLinkDialog: false,
       showInsertFileDialog: false,
@@ -65,15 +63,6 @@ class MarkdownEditor extends React.Component {
 
     this.timer = null;
 
-    if (this.state.collabServer) {
-      const socket = io(this.state.collabServer);
-      this.socket = socket;
-      socket.on('presence', (data) => this.receivePresenceData(data));
-      socket.on('repo_update', (data) => this.receiveUpdateData(data));
-      socket.on('connect', () => {
-        this.socket_id = socket.id;
-      });
-    }
     this.editorRef = React.createRef();
     this.isParticipant = false;
     this.editorSelection = null;
@@ -92,18 +81,6 @@ class MarkdownEditor extends React.Component {
     }
   };
 
-  emitSwitchEditor = (is_editing = false) => {
-    if (userInfo && this.state.collabServer) {
-      const { repoID, path } = this.state.fileInfo;
-      this.socket.emit('presence', {
-        request: 'editing',
-        doc_id: CryptoJS.MD5(repoID + path).toString(),
-        user: userInfo,
-        is_editing,
-      });
-    }
-  };
-
   receiveUpdateData(data) {
     let currentTime = new Date();
     if ((parseFloat(currentTime - this.lastModifyTime) / 1000) <= 5) {
diff --git a/frontend/src/pages/plain-markdown-editor/index.js b/frontend/src/pages/plain-markdown-editor/index.js
index fb1c739b7d..7a76e94a55 100644
--- a/frontend/src/pages/plain-markdown-editor/index.js
+++ b/frontend/src/pages/plain-markdown-editor/index.js
@@ -22,7 +22,6 @@ const propTypes = {
 };
 
 const { repoID, filePath, fileName, isLocked, lockedByMe } = window.app.pageOptions;
-const { seafileCollabServer } = window.app.config;
 const userInfo = window.app.userInfo;
 
 const initOptions = {
@@ -41,7 +40,6 @@ const initOptions = {
     id: '',
   },
   editorMode: 'plain',
-  collabServer: seafileCollabServer ? seafileCollabServer : null,
   showMarkdownEditorDialog: false,
   showShareLinkDialog: false,
   showInsertFileDialog: false,
diff --git a/frontend/src/utils/collab-server.js b/frontend/src/utils/collab-server.js
deleted file mode 100644
index e0ee905bde..0000000000
--- a/frontend/src/utils/collab-server.js
+++ /dev/null
@@ -1,43 +0,0 @@
-import io from 'socket.io-client';
-import { name, username, contactEmail, seafileCollabServer } from './constants';
-
-const socket = (seafileCollabServer !== '') ? io(seafileCollabServer) : undefined;
-
-class CollabServer {
-
-  watchRepo(repoID, fn) {
-    if (!socket) {
-      return;
-    }
-    socket.emit('repo_update', {
-      request: 'watch_update',
-      repo_id: repoID,
-      user: {
-        name: name,
-        username: username,
-        contact_email: contactEmail,
-      },
-    });
-    socket.on('repo_update', fn);
-  }
-
-  unwatchRepo(repoID, fn) {
-    if (!socket) {
-      return;
-    }
-    socket.emit('repo_update', {
-      request: 'unwatch_update',
-      repo_id: repoID,
-      user: {
-        name: name,
-        username: username,
-        contact_email: contactEmail,
-      },
-    });
-    socket.off('repo_update', fn);
-  }
-}
-
-const collabServer = new CollabServer();
-
-export default collabServer;
diff --git a/frontend/src/utils/constants.js b/frontend/src/utils/constants.js
index 41915301ce..ef3d1aae86 100644
--- a/frontend/src/utils/constants.js
+++ b/frontend/src/utils/constants.js
@@ -19,7 +19,6 @@ export const logoWidth = window.app.config.logoWidth;
 export const logoHeight = window.app.config.logoHeight;
 export const isPro = window.app.config.isPro === 'True';
 export const isDBSqlite3 = window.app.config.isDBSqlite3;
-export const isDocs = window.app.config.isDocs === 'True';
 export const lang = window.app.config.lang;
 export const fileServerRoot = window.app.config.fileServerRoot;
 export const useGoFileserver = window.app.config.useGoFileserver;
@@ -32,7 +31,6 @@ export const enableRepoAutoDel = window.app.config.enableRepoAutoDel;
 
 // pageOptions
 export const trashReposExpireDays = window.app.pageOptions.trashReposExpireDays;
-export const seafileCollabServer = window.app.pageOptions.seafileCollabServer;
 export const name = window.app.pageOptions.name;
 export const contactEmail = window.app.pageOptions.contactEmail;
 export const username = window.app.pageOptions.username;
diff --git a/seahub/base/context_processors.py b/seahub/base/context_processors.py
index 7dec1dd6cf..721db067f0 100644
--- a/seahub/base/context_processors.py
+++ b/seahub/base/context_processors.py
@@ -22,7 +22,7 @@ from seahub.settings import SEAFILE_VERSION, SITE_DESCRIPTION, \
     SHOW_REPO_DOWNLOAD_BUTTON, SITE_ROOT, ENABLE_GUEST_INVITATION, \
     FAVICON_PATH, APPLE_TOUCH_ICON_PATH, THUMBNAIL_SIZE_FOR_ORIGINAL, \
     MEDIA_ROOT, SHOW_LOGOUT_ICON, CUSTOM_LOGO_PATH, CUSTOM_FAVICON_PATH, \
-    ENABLE_SEAFILE_DOCS, LOGIN_BG_IMAGE_PATH, THUMBNAIL_DEFAULT_SIZE, \
+    LOGIN_BG_IMAGE_PATH, THUMBNAIL_DEFAULT_SIZE, \
     CUSTOM_LOGIN_BG_PATH, ENABLE_SHARE_LINK_REPORT_ABUSE, \
     PRIVACY_POLICY_LINK, TERMS_OF_SERVICE_LINK, ENABLE_SEADOC, THUMBNAIL_SIZE_FOR_GRID, \
     FILE_SERVER_ROOT, ENABLE_WHITEBOARD, ENABLE_SEAFILE_AI
@@ -162,7 +162,6 @@ def base(request):
         'show_logout_icon': SHOW_LOGOUT_ICON,
         'is_pro': True if is_pro_version() else False,
         'is_db_sqlite3': IS_DB_SQLITE3,
-        'is_docs': ENABLE_SEAFILE_DOCS,
         'enable_upload_folder': dj_settings.ENABLE_UPLOAD_FOLDER,
         'enable_resumable_fileupload': dj_settings.ENABLE_RESUMABLE_FILEUPLOAD,
         'service_url': get_service_url().rstrip('/'),
diff --git a/seahub/settings.py b/seahub/settings.py
index 1653973de9..509049f49b 100644
--- a/seahub/settings.py
+++ b/seahub/settings.py
@@ -491,8 +491,6 @@ ENABLE_SHARE_TO_DEPARTMENT = True
 # interval for request unread notifications
 UNREAD_NOTIFICATIONS_REQUEST_INTERVAL = 3 * 60 # seconds
 
-# Enable seafile docs
-ENABLE_SEAFILE_DOCS = False
 
 ENABLE_CONVERT_TO_TEAM_ACCOUNT = False
 
@@ -892,21 +890,7 @@ FILESERVER_TOKEN_ONCE_ONLY = True
 SEND_EMAIL_ON_ADDING_SYSTEM_MEMBER = True # Whether to send email when a system staff adding new member.
 SEND_EMAIL_ON_RESETTING_USER_PASSWD = True # Whether to send email when a system staff resetting user's password.
 
-##########################
-# Settings for Extra App #
-##########################
 
-##########################
-# Settings for frontend  #
-##########################
-
-SEAFILE_COLLAB_SERVER = ''
-
-##########################
-# Settings for dtable web  #
-##########################
-
-DTABLE_WEB_SERVER = ''
 
 ##########################
 # Settings for seadoc    #
diff --git a/seahub/templates/base_for_react.html b/seahub/templates/base_for_react.html
index 20d826fdc0..bc06191f98 100644
--- a/seahub/templates/base_for_react.html
+++ b/seahub/templates/base_for_react.html
@@ -48,7 +48,6 @@
             loginUrl: '{{ LOGIN_URL }}',
             isPro: '{{ is_pro }}',
             isDBSqlite3: {% if is_db_sqlite3 %} true {% else %} false {% endif %},
-            isDocs: '{{ is_docs }}',
             lang: '{{ LANGUAGE_CODE }}',
             fileServerRoot: '{{ FILE_SERVER_ROOT }}',
             enableRepoAutoDel: {% if enable_repo_auto_del %} true {% else %} false {% endif %},
@@ -59,7 +58,6 @@
         },
         pageOptions: {
             csrfToken: "{{ csrf_token }}",
-            seafileCollabServer: '{{seafile_collab_server}}',
             name: "{{request.user.username|email2nickname|escapejs}}",
             contactEmail: "{{request.user.username|email2contact_email|escapejs}}",
             username: "{{request.user.username|escapejs}}",
diff --git a/seahub/templates/file_view_react.html b/seahub/templates/file_view_react.html
index 678ad5100a..8052977bdd 100644
--- a/seahub/templates/file_view_react.html
+++ b/seahub/templates/file_view_react.html
@@ -36,7 +36,6 @@ window.app.pageOptions = {
   fileType: '{{ filetype }}',
   parentDir: '{{ parent_dir|escapejs }}',
   err: '{{ err }}',
-  seafileCollabServer: '{{seafile_collab_server}}',
   contactEmail: "{{request.user.username|email2contact_email|escapejs}}",
   lockedByMe: {% if locked_by_me %}true{% else %}false{% endif %},
   canLockUnlockFile: {% if can_lock_unlock_file %}true{% else %}false{% endif %},
diff --git a/seahub/templates/markdown_file_view_react.html b/seahub/templates/markdown_file_view_react.html
index 334dba8150..b75c874b65 100644
--- a/seahub/templates/markdown_file_view_react.html
+++ b/seahub/templates/markdown_file_view_react.html
@@ -31,9 +31,7 @@
                   siteRoot: '{{ SITE_ROOT }}',
                   serviceUrl: '{{ serviceUrl }}',
                   isPro: '{{ is_pro }}',
-                  isDocs: '{{ is_docs }}',
                   lang: '{{ LANGUAGE_CODE }}',
-                  seafileCollabServer: '{{ seafile_collab_server}}',
               },
               pageOptions: {
                   repoID: '{{ repo.id }}',
diff --git a/seahub/templates/plain_markdown_file_view_react.html b/seahub/templates/plain_markdown_file_view_react.html
index 614ca17427..a2fc9d8080 100644
--- a/seahub/templates/plain_markdown_file_view_react.html
+++ b/seahub/templates/plain_markdown_file_view_react.html
@@ -31,9 +31,7 @@
                   siteRoot: '{{ SITE_ROOT }}',
                   serviceUrl: '{{ serviceUrl }}',
                   isPro: '{{ is_pro }}',
-                  isDocs: '{{ is_docs }}',
                   lang: '{{ LANGUAGE_CODE }}',
-                  seafileCollabServer: '{{ seafile_collab_server}}',
               },
               pageOptions: {
                   repoID: '{{ repo.id }}',
diff --git a/seahub/views/__init__.py b/seahub/views/__init__.py
index f76bc4fc76..9d768d945d 100644
--- a/seahub/views/__init__.py
+++ b/seahub/views/__init__.py
@@ -56,9 +56,9 @@ from seahub.settings import AVATAR_FILE_STORAGE, ENABLE_REPO_SNAPSHOT_LABEL, \
     SHARE_LINK_EXPIRE_DAYS_MIN, ENABLE_METADATA_MANAGEMENT, \
     SHARE_LINK_EXPIRE_DAYS_MAX, SHARE_LINK_EXPIRE_DAYS_DEFAULT, \
     UPLOAD_LINK_EXPIRE_DAYS_MIN, UPLOAD_LINK_EXPIRE_DAYS_MAX, UPLOAD_LINK_EXPIRE_DAYS_DEFAULT, \
-    SEAFILE_COLLAB_SERVER, ENABLE_RESET_ENCRYPTED_REPO_PASSWORD, \
+    ENABLE_RESET_ENCRYPTED_REPO_PASSWORD, \
     ADDITIONAL_SHARE_DIALOG_NOTE, ADDITIONAL_ABOUT_DIALOG_LINKS, \
-    DTABLE_WEB_SERVER, SEADOC_SERVER_URL, SHOW_WECHAT_SUPPORT_GROUP
+    SEADOC_SERVER_URL, SHOW_WECHAT_SUPPORT_GROUP
 
 from seahub.ocm.settings import ENABLE_OCM, OCM_REMOTE_SERVERS
 from seahub.ocm_via_webdav.settings import ENABLE_OCM_VIA_WEBDAV
@@ -1112,7 +1112,6 @@ def react_fake_view(request, **kwargs):
         "guide_enabled": guide_enabled,
         'trash_repos_expire_days': expire_days if expire_days > 0 else 30,
         'max_upload_file_size': max_upload_file_size,
-        'seafile_collab_server': SEAFILE_COLLAB_SERVER,
         'storages': get_library_storages(request),
         'library_templates': list(LIBRARY_TEMPLATES.keys()),
         'enable_repo_snapshot_label': settings.ENABLE_REPO_SNAPSHOT_LABEL,
diff --git a/seahub/views/file.py b/seahub/views/file.py
index e19dcdf4d6..f3cb84febc 100644
--- a/seahub/views/file.py
+++ b/seahub/views/file.py
@@ -85,7 +85,7 @@ if HAS_OFFICE_CONVERTER:
 
 import seahub.settings as settings
 from seahub.settings import FILE_ENCODING_LIST, FILE_PREVIEW_MAX_SIZE, \
-    FILE_ENCODING_TRY_LIST, MEDIA_URL, SEAFILE_COLLAB_SERVER, ENABLE_WATERMARK, \
+    FILE_ENCODING_TRY_LIST, MEDIA_URL, ENABLE_WATERMARK, \
     SHARE_LINK_EXPIRE_DAYS_MIN, SHARE_LINK_EXPIRE_DAYS_MAX, SHARE_LINK_PASSWORD_MIN_LENGTH, \
     SHARE_LINK_FORCE_USE_PASSWORD, SHARE_LINK_PASSWORD_STRENGTH_LEVEL, \
     SHARE_LINK_EXPIRE_DAYS_DEFAULT, ENABLE_SHARE_LINK_REPORT_ABUSE, SEADOC_SERVER_URL, \
@@ -640,7 +640,6 @@ def view_lib_file(request, repo_id, path):
         'share_link_expire_days_min': SHARE_LINK_EXPIRE_DAYS_MIN,
         'share_link_expire_days_max': SHARE_LINK_EXPIRE_DAYS_MAX,
         'can_download_file': parse_repo_perm(permission).can_download,
-        'seafile_collab_server': SEAFILE_COLLAB_SERVER,
         'enable_metadata_management': ENABLE_METADATA_MANAGEMENT,
         'file_download_url': gen_file_get_url_new(repo_id, path),
         'mobile_login': mobile_login,
@@ -2237,7 +2236,6 @@ def view_sdoc_revision(request, repo_id, revision_id):
         'share_link_expire_days_min': SHARE_LINK_EXPIRE_DAYS_MIN,
         'share_link_expire_days_max': SHARE_LINK_EXPIRE_DAYS_MAX,
         'can_download_file': parse_repo_perm(permission).can_download,
-        'seafile_collab_server': SEAFILE_COLLAB_SERVER,
         'mobile_login': mobile_login,
     }
 
diff --git a/seahub/views/repo.py b/seahub/views/repo.py
index e11c28fb9d..ffd05811b1 100644
--- a/seahub/views/repo.py
+++ b/seahub/views/repo.py
@@ -31,7 +31,7 @@ from seahub.settings import ENABLE_UPLOAD_FOLDER, \
     ENABLE_RESUMABLE_FILEUPLOAD, ENABLE_VIDEO_THUMBNAIL, \
     THUMBNAIL_ROOT, THUMBNAIL_DEFAULT_SIZE, THUMBNAIL_SIZE_FOR_GRID, \
     MAX_NUMBER_OF_FILES_FOR_FILEUPLOAD, SHARE_LINK_EXPIRE_DAYS_MIN, \
-    SHARE_LINK_EXPIRE_DAYS_MAX, SEAFILE_COLLAB_SERVER, \
+    SHARE_LINK_EXPIRE_DAYS_MAX, \
     ENABLE_SHARE_LINK_REPORT_ABUSE, ENABLE_PDF_THUMBNAIL
 from seahub.utils.file_types import IMAGE, VIDEO, XMIND
 from seahub.thumbnail.utils import get_share_link_thumbnail_src
@@ -235,7 +235,6 @@ def view_lib_as_wiki(request, repo_id, path):
         user_can_write = False
 
     return render(request, 'view_lib_as_wiki.html', {
-        'seafile_collab_server': SEAFILE_COLLAB_SERVER,
         'repo_id': repo_id,
         'service_url': get_service_url().rstrip('/'),
         'initial_path': path,