To upgrade from OpenLDAP 2.2 to OpenLDAP 2.3 on CentOS 4.3, you need to update yum, the automatic updater/package installer/remover for RPM systems. Then you’re ready to upgrade your OpenLDAP packages. First, point yum at the CentOS development repository, or repo, by adding these lines to /etc/yum.repos.d/CentOS-Base.repo:

name=CentOS-$releasever - Testing
$releasever/testing/$basearch/ enabled=1 gpgcheck=1 gpgkey=

Next, upgrade your OpenLDAP packages using this command:

# yum -y install openldap.i386 openl
dap-clients.i386 openldap-devel.i386 openldap-servers.i386

Upgrading may take a while, as yum needs to update all packages related to OpenLDAP as well.