https://bugs.openldap.org/show_bug.cgi?id=9485
--- Comment #7 from Quanah Gibson-Mount quanah@openldap.org --- (In reply to Sam James from comment #6)
2.4.x is the current stable release, so that's the relevance.
OpenLDAP 2.4 requires autoconf 2.59, and that will not change as it's not open for development.
OpenLDAP 2.5 is near release and has already been updated for autoconf 2.69.
Again, a patch against master is welcome, but likely won't be applied until OpenlDAP 2.6.