No wheezy-updates repository yet, apparently

templates/os/sources/sources.list.erb

@@ -28,6 +28,7 @@ deb-src http://debian.stanford.edu/debian <%= lsbdistcodename %> main non-free c
 # The archive that publishes updates for security vulnerabilities.
 deb     http://debian.stanford.edu/debian-security <%= lsbdistcodename %>/updates main non-free contrib
 deb-src http://debian.stanford.edu/debian-security <%= lsbdistcodename %>/updates main non-free contrib
+<% if lsbdistcodename == 'wheezy' -%>
 
 # The updates Debian archive and source tree.  This is a replacement for
 # the volatile archive and contains packages that change more frequently
@@ -35,3 +36,4 @@ deb-src http://debian.stanford.edu/debian-security <%= lsbdistcodename %>/update
 deb     http://debian.stanford.edu/debian <%= lsbdistcodename %>-updates main non-free contrib
 deb-src http://debian.stanford.edu/debian <%= lsbdistcodename %>-updates main non-free contrib
 <% end -%>
+<% end -%>