Thanks Brian, I upgraded apt-cacher to 1.6.4ubuntu2 from intreprid- proposed, which solved the problem.
I was confused by the launchpad janitor comment above: "This bug was fixed in the package apt-cacher - 1.6.4ubuntu1" I have also commented on #291606 -- "Failed Upgrade tool signature" when using do-release-upgrade https://bugs.launchpad.net/bugs/156070 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs