diff --git a/ietf/meeting/helpers.py b/ietf/meeting/helpers.py
index 85c687d42..9498d4f76 100644
--- a/ietf/meeting/helpers.py
+++ b/ietf/meeting/helpers.py
@@ -194,6 +194,7 @@ def preprocess_assignments_for_agenda(assignments_queryset, meeting, extra_prefe
     for a in assignments:
         if a.session:
             a.session.historic_group = None
+            a.session.order_number = None
 
             if a.session.group and a.session.group not in groups:
                 groups.append(a.session.group)
@@ -216,6 +217,9 @@ def preprocess_assignments_for_agenda(assignments_queryset, meeting, extra_prefe
                 if a.session.historic_group.parent_id:
                     parent_id_set.add(a.session.historic_group.parent_id)
 
+            l = sessions_for_groups.get((a.session.group, a.session.type_id), [])
+            a.session.order_number = l.index(a) + 1 if a in l else 0
+            
     parents = Group.objects.filter(pk__in=parent_id_set)
     parent_replacements = find_history_replacements_active_at(parents, meeting_time)
 
diff --git a/ietf/meeting/views.py b/ietf/meeting/views.py
index 986bbe66d..57dabc3d4 100644
--- a/ietf/meeting/views.py
+++ b/ietf/meeting/views.py
@@ -2305,6 +2305,8 @@ def session_details(request, num, acronym):
             qs = [p for p in qs if p.document.get_state_slug(p.document.type_id)!='deleted']
             session.type_counter.update([p.document.type.slug for p in qs])
 
+        session.order_number = session.order_in_meeting()
+
     # we somewhat arbitrarily use the group of the last session we get from
     # get_sessions() above when checking can_manage_session_materials()
     can_manage = can_manage_session_materials(request.user, session.group, session)