https://bugs.openldap.org/show_bug.cgi?id=9888
--- Comment #5 from Quanah Gibson-Mount quanah@openldap.org --- (In reply to Howard Chu from comment #4)
Also note that the OID is part of the index key, so reusing OIDs for different attributes will absolutely corrupt indices.
This is a long standing rule - OIDs of existing attributes must never be changed or reused for different attributes. If you're doing schema changes of that sort, you must always assign entirely new OIDs to ever changed attribute.
Hm, that's odd. One of my first conversations with you back at Stanford was when we hit an issue with AD that it stores knowledge of the attribute OIDs and OpenLDAP does not (back with OpenLDAP 2.1). We'd run into an issue where AD had problems with a schema change when an OID was re-used.
Past that point, this has not been a problem for OpenLDAP 2.1 through OpenLDAP 2.4 where this was made extensive use of at both Stanford and at Zimbra (I just went back and checked the commit history of the Zimbra schema to confirm).