diff -Nru horizon-13.0.1/debian/changelog horizon-13.0.1/debian/changelog
--- horizon-13.0.1/debian/changelog	2018-11-02 12:08:50.000000000 +0900
+++ horizon-13.0.1/debian/changelog	2018-11-12 14:30:31.000000000 +0900
@@ -1,3 +1,9 @@
+horizon (3:13.0.1-0ubuntu4~cloud0) xenial-queens; urgency=medium
+
+  * Flushing memcached after upgrading(LP: #1802226)
+
+ -- Seyeong Kim <seyeong.kim@canonical.com>  Mon, 12 Nov 2018 14:30:31 +0900
+
 horizon (3:13.0.1-0ubuntu3~cloud0) xenial-queens; urgency=medium
 
   * New update for the Ubuntu Cloud Archive.
diff -Nru horizon-13.0.1/debian/openstack-dashboard.postinst horizon-13.0.1/debian/openstack-dashboard.postinst
--- horizon-13.0.1/debian/openstack-dashboard.postinst	2018-10-15 23:02:56.000000000 +0900
+++ horizon-13.0.1/debian/openstack-dashboard.postinst	2018-11-12 14:30:31.000000000 +0900
@@ -24,6 +24,11 @@
     python manage.py compress --force 2>&1 > /dev/null
   )
 
+  (
+    echo "Flushing cached html in memcached..."
+    echo 'flush_all' | nc localhost 11211 2>&1 > /dev/null
+  )
+
   if [ -e /var/lib/openstack-dashboard ] ; then
     chown -R horizon:horizon /var/lib/openstack-dashboard
   fi