[bitfolk] Problems upgrading to Ubuntu Xenial Xerus (16.04)

Hi all, I was looking to upgrade my VPS to the latest Ubuntu release this afternoon but ran across a problem. Whenever I try to run "do-release-upgrade” I receive the following error: Checking for a new Ubuntu release Get:1 Upgrade tool signature [836 B] Get:2 Upgrade tool [1,265 kB] Fetched 1,266 kB in 0s (0 B/s) authenticate 'xenial.tar.gz' against 'xenial.tar.gz.gpg' gpg exited 1 Debug information: gpg: Signature made Wed 07 Dec 2016 09:10:01 GMT using RSA key ID C0B21F32 gpg: /tmp/ubuntu-release-upgrader-r7c80csz/trustdb.gpg: trustdb created gpg: BAD signature from "Ubuntu Archive Automatic Signing Key (2012) <ftpmaster@ubuntu.com<mailto:ftpmaster@ubuntu.com>>" Authentication failed Authenticating the upgrade failed. There may be a problem with the network or with the server. Searching online<http://askubuntu.com/questions/842706/how-to-upgrade-ubuntu-if-i-…ed>, this looks like it could be a problem with the xenial.tar.gz file on the local repo cache. Has anyone else had similar problems, and if so, how did you resolve them? I suppose beyond that, has anyone successfully upgraded their Ubuntu VPS to 16.04? Were there any problems along the way? Thanks, Paul