An Anaconda upgrade is mandatory in order to support Intel Matrix RAID (ie. RAID5 and RAID10) in the installer for the dmraid 5.2.z package.
Since rel-eng doesn't make new distribution trees for z stream, there's no point in doing an anaconda update. There will never be new installation media for 5.2 to make use of this fix. z-stream for anaconda therefore doesn't make any sense. The customer will have to wait for 5.3 to come out with the proper fix from 437184 in order to install.