Comment 18 for bug 1679435

Tested on Xenial.

gnome-software:
  Installed: 3.20.1+git20170427.0.3d09239-0ubuntu1~xenial1
  Candidate: 3.20.1+git20170427.0.3d09239-0ubuntu1~xenial1
  Version table:
 *** 3.20.1+git20170427.0.3d09239-0ubuntu1~xenial1 500
        500 http://gb.archive.ubuntu.com/ubuntu xenial-proposed/main amd64 Packages
        100 /var/lib/dpkg/status
     3.20.1+git20170208.0.a34b091-0ubuntu1~xenial1 500
        500 http://gb.archive.ubuntu.com/ubuntu xenial-updates/main amd64 Packages
     3.20.1+git20160420.1.ca63436.ubuntu-xenial-0ubuntu2 500
        500 http://gb.archive.ubuntu.com/ubuntu xenial/main amd64 Packages

And I can confirm that it worked as expected.