Trying to load iPhoto update 9.6.1

We have an iMac 27" mid 2011 running OS X El Capitan 10.11, and Macbook Pro 13" late 2011 a running OS X Yosemite 10.10.5. We're finally getting around to doing some updates (those that pop up automatically saying updates available). All were successfully updated but one. The iPhoto version 9.6.1 release Mar 19, 2015 will not update on either computer. After trying to update for about five minutes, each time it fails and we get this: "This item is temporarily unavailable. Try again later." Any idea what's going on? Is it because I did not update back in March? Thanks