I don't remember the details, but I'm pretty sure there's no binary compatibility between database files created by OpenLDAP 2.1 and OpenLDAP 2.3; in general, you shouldn't expect anything like that when moving across minor versions. As Quanah already pointed out, migration from minor to minor should be done via (old)slapcat/(new)slapadd, which,
s/minor to minor/major to major/
--Quanah
-- Quanah Gibson-Mount Principal Software Developer ITS/Shared Application Services Stanford University GnuPG Public Key: http://www.stanford.edu/~quanah/pgp.html