back-sql was updated in 2.4.27, back-meta in 2.4.33
Note: You will need to continue to use the older {{slapd.conf}}(5)
configuration system if your OpenLDAP installation requires the use of one
or more backends or overlays that have not been updated to use the
-{{slapd-config}}(5) system. As of OpenLDAP 2.4.25, the only official backends
-that have not yet been updated to use {{slapd-config}}(5) are {{slapd-meta}}(5)
-and {{slapd-sql}}(5). There may be additional contributed or experimental
+{{slapd-config}}(5) system. As of OpenLDAP 2.4.33, all of the official
+backends have been updated. There may be additional contributed or experimental
overlays that also have not been updated.