diff -Nru update-notifier-3.180/debian/changelog update-notifier-3.181/debian/changelog
--- update-notifier-3.180/debian/changelog	2017-06-21 12:44:00.000000000 +0000
+++ update-notifier-3.181/debian/changelog	2017-06-28 20:25:25.000000000 +0000
@@ -1,3 +1,9 @@
+update-notifier (3.181) artful; urgency=medium
+
+  * Fix APT sandboxing for data downloads failing (LP: #1522675)
+
+ -- Julian Andres Klode <juliank@ubuntu.com>  Wed, 28 Jun 2017 22:25:25 +0200
+
 update-notifier (3.180) artful; urgency=medium
 
   * Fix autopkgtest pep8 new error in artful:
diff -Nru update-notifier-3.180/debian/control update-notifier-3.181/debian/control
--- update-notifier-3.180/debian/control	2017-06-21 12:42:36.000000000 +0000
+++ update-notifier-3.181/debian/control	2017-06-28 20:25:10.000000000 +0000
@@ -43,7 +43,7 @@
 Package: update-notifier-common
 Replaces: update-notifier (<< 0.75.1)
 Architecture: all
-Pre-Depends: dpkg (>= 1.15.7.2)
+Pre-Depends: dpkg (>= 1.15.7.2), apt (>= 1.1~)
 Depends: ${shlibs:Depends},
          ${misc:Depends},
          python3:any,
diff -Nru update-notifier-3.180/debian/update-notifier-common.postinst update-notifier-3.181/debian/update-notifier-common.postinst
--- update-notifier-3.180/debian/update-notifier-common.postinst	2017-06-21 12:42:36.000000000 +0000
+++ update-notifier-3.181/debian/update-notifier-common.postinst	2017-06-28 20:25:25.000000000 +0000
@@ -20,6 +20,10 @@
 	exit 0
 fi
 
+# Ensure permissions are correct, otherwise downloading sandboxing fails
+chown -R _apt:root /var/lib/update-notifier/package-data-downloads/partial/
+chmod 700 /var/lib/update-notifier/package-data-downloads/partial/
+
 # Run this when configuring as well, since we may not be triggered at all
 # depending on package unpack order.
 /usr/lib/update-notifier/package-data-downloader