--- a/libervia/backend/plugins/plugin_xep_0424.py	Fri Jul 04 12:28:40 2025 +0200
+++ b/libervia/backend/plugins/plugin_xep_0424.py	Fri Jul 04 12:30:20 2025 +0200
@@ -16,7 +16,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 import time
-from typing import Any, Dict
+from typing import Any, Dict, cast
 
 from sqlalchemy.orm.attributes import flag_modified
 from twisted.internet import defer
@@ -31,6 +31,7 @@
 from libervia.backend.core.i18n import D_, _
 from libervia.backend.core.log import getLogger
 from libervia.backend.memory.sqla_mapping import History
+from libervia.backend.plugins.plugin_xep_0428 import XEP_0428
 from libervia.backend.tools.common import data_format
 
 log = getLogger(__name__)
@@ -111,8 +112,10 @@
         message_elt["type"] = history.type
         retract_elt = message_elt.addElement((NS_MESSAGE_RETRACT, "retract"))
         retract_elt["id"] = retract_id
-        self.host.plugins["XEP-0428"].add_fallback_elt(
+        fallback = cast(XEP_0428, self.host.plugins["XEP-0428"])
+        fallback.add_fallback_elt(
             message_elt,
+            NS_MESSAGE_RETRACT,
             "[A message retraction has been requested, but your client doesn't support "
             "it]",
         )