Emmanuel Dreyfus wrote:

I have a VoIP phone that insist on having ORDERING set on sn and givenName in core.schema. Is there any smart way of doing it without modifying the core.schema file?

I don't think so. But maybe you can convince the phone to search for (sn:caseIgnoreOrderingMatch:=foo), which means sn < "foo".

If you do modify schema elements which are in use, you must rebuild the database. Or possibly slapindex is enough.