OpenLDAP 2.4.21 is now considered the most "stable" release of OpenLDAP Software available: http://www.openldap.org/software/download/
The OPENLDAP_STABLE cvs(1) tag has been moved forward to OPENLDAP_REL_ENG_2_4_21: http://www.openldap.org/software/repo.html
For definitions of "stable" and "release" versions of OpenLDAP Software, please see the FAQ: http://www.openldap.org/faq/?file=225
Users of prior "release" and "stable" versions of OpenLDAP Software are strongly encouraged to upgrade.
-- The OpenLDAP Project
openldap-announce@openldap.org