diff --git a/sat/plugins/plugin_xep_0384.py b/sat/plugins/plugin_xep_0384.py
index 6bcea52b..8785be9e 100644
--- a/sat/plugins/plugin_xep_0384.py
+++ b/sat/plugins/plugin_xep_0384.py
@@ -1107,6 +1107,8 @@ class OMEMO:
     between the two is maintained. MUC messages are supported next to one to one messages.
     For trust management, the two trust models "BTBV" and "manual" are supported.
     """
+    NS_TWOMEMO = twomemo.twomemo.NAMESPACE
+    NS_OLDMEMO = oldmemo.oldmemo.NAMESPACE
 
     # For MUC/MIX message stanzas, the <to/> affix is a MUST
     SCE_PROFILE_GROUPCHAT = SCEProfile(