More overlays:
- slapo-dds (Dynamic Directory Services, RFC 2589)
- slapo-memberof (reverse group membership maintenance)
New features in existing ones:
- slapo-pcache allows cache inspection/maintenance/hot restart
- slapo-rwm can safely interoperate with other overlays
New features in slapd:
- monitoring of back-{b,h}db: cache fill-in, non-indexed searches, ...
- session tracking control (draft-wahl-ldap-session)
- subtree delete in back-sql (draft-armijo-ldap-treedelete)
New features in libldap:
- ldap_sync client API (LDAP Content Sync Operation, RFC 4533)
New clients and tools:
- ldapexop for arbitrary extended operations
- complete support of controls in request/response for all clients
I can't seem to remember anything else that's not in 2.3 yet.