The Buckminster build automatically promotes downloads and updates, so no cron job help is necessary.

The updates can be checked by looking for the new entry on http://www.eclipse.org/modeling/mdt/downloads/?project=ocl
or installing new software from e.g. http://download.eclipse.org/modeling/mdt/ocl/updates/milestones/6.4.0/S201408191307

However operations on composite repositories are not automated, partly because they are sufficiently important to deserve manual attention. 

A new milestone build can be added to the composite repository by:

logon to build.eclipse.org
cd downloads/modeling/mdt/ocl/updates/milestones/6.4.0
ant -f /shared/modeling/tools/promotion/manage-composite.xml add -Dchild.repository=S201408191307 [ -Dcomposite.name="OCL 6.4.0 milestones" ]

(This can be checked by installing new software from e.g. http://download.eclipse.org/modeling/mdt/ocl/updates/milestones/6.4.0)

The Photon aggregator is configured by GIT\org.eclipse.simrel.build\ocl.b3aggrcon to use an explicit milestone entry

So edit ocl.b3aggrcon to update 
location="http://download.eclipse.org/modeling/mdt/ocl/updates/milestones/6.4.0/S201408191307"
push to upstream master and start a new build at https://hudson.eclipse.org/hudson/job/simrel.neon.runaggregator/

Once a release has been promoted update ocl.b3aggrcon to the final release
location="http://download.eclipse.org/modeling/mdt/ocl/updates/releases/6.4.0"

Downloads are accessible at
cd downloads/modeling/mdt/ocl/downloads/drops/6.4.0

Archives are accessible at
cd /home/data/httpd/archive.eclipse.org/modeling/mdt/ocl/downloads/drops