diff --git a/chat/indico_chat/controllers/base.py b/chat/indico_chat/controllers/base.py
index bfd79e8..edcb353 100644
--- a/chat/indico_chat/controllers/base.py
+++ b/chat/indico_chat/controllers/base.py
@@ -25,8 +25,6 @@ from indico_chat.util import is_chat_admin
 
 
 class RHChatManageEventBase(RHConferenceModifBase):
-    ALLOW_LEGACY_IDS = False
-
     def _checkParams(self, params):
         RHConferenceModifBase._checkParams(self, params)
         self.event_id = int(self._conf.id)
diff --git a/chat/indico_chat/controllers/event.py b/chat/indico_chat/controllers/event.py
index 05b1fc0..79d0d81 100644
--- a/chat/indico_chat/controllers/event.py
+++ b/chat/indico_chat/controllers/event.py
@@ -27,8 +27,6 @@ from indico_chat.views import WPChatEventPage
 class RHChatEventPage(RHConferenceBaseDisplay):
     """Lists the public chatrooms in a conference"""
 
-    ALLOW_LEGACY_IDS = False
-
     def _process(self):
         chatrooms = ChatroomEventAssociation.find_for_event(self._conf).all()
         cols = set()
diff --git a/chat/indico_chat/plugin.py b/chat/indico_chat/plugin.py
index 9b75aac..4af754e 100644
--- a/chat/indico_chat/plugin.py
+++ b/chat/indico_chat/plugin.py
@@ -113,8 +113,6 @@ class ChatPlugin(IndicoPlugin):
         self.register_js_bundle('chat_js', 'js/chat.js')
 
     def inject_event_header(self, event, **kwargs):
-        if event.has_legacy_id:
-            return ''
         chatrooms = ChatroomEventAssociation.find_for_event(event).all()
         if not chatrooms:
             return ''
@@ -150,8 +148,6 @@ class ChatPlugin(IndicoPlugin):
             return url_for_plugin('chat.manage_rooms', event)
 
     def event_deleted(self, event, **kwargs):
-        if event.has_legacy_id:
-            return
         for event_chatroom in ChatroomEventAssociation.find_for_event(event, include_hidden=True):
             chatroom_deleted = event_chatroom.delete()
             notify_deleted(event_chatroom.chatroom, event, None, chatroom_deleted)
@@ -162,8 +158,7 @@ class ChatPlugin(IndicoPlugin):
 
 class ChatroomCloner(EventCloner):
     def get_options(self):
-        enabled = (not self.event.has_legacy_id and
-                   bool(ChatroomEventAssociation.find_for_event(self.event, include_hidden=True).count()))
+        enabled = bool(ChatroomEventAssociation.find_for_event(self.event, include_hidden=True).count())
         return {'chatrooms': (_('Chatrooms'), enabled, False)}
 
     def clone(self, new_event, options):