--- a/misc/migration/3.3.5_Any.py	Wed Mar 27 14:53:40 2013 +0100
+++ b/misc/migration/3.3.5_Any.py	Wed Mar 27 15:38:05 2013 +0100
@@ -1,8 +1,1 @@
-# some entities have been added before schema entities, fix the 'is' and
-# 'is_instance_of' relations
-for rtype in ('is', 'is_instance_of'):
-    sql('INSERT INTO %s_relation '
-        'SELECT X.eid, ET.cw_eid FROM entities as X, cw_CWEType as ET '
-        'WHERE X.type=ET.cw_name AND NOT EXISTS('
-        '      SELECT 1 from is_relation '
-        '      WHERE eid_from=X.eid AND eid_to=ET.cw_eid)' % rtype)
+raise NotImplementedError("Cannot migrate such an old version. Use intermediate Cubiweb version (try 3.16.x)")