Comment 12 for bug 1573408

Ok, well, that's is probably a separate issue that is no fault of the gnome-software package. Thanks for confirming that the fix in xenial-proposed is working for you.

For the issue with "sudo apt-get update" getting weak-signature-key-rejections, I'm not sure what the canonical bug will become, but I've discover it already reported here:

As the gnome-software bug seems on its way to becoming "fix-released", my focus will be shifting towards the weak-signature-key-rejections issue.