Comment 2 for bug 1053896

People without the package from precise-proposed can no longer upgrade to quantal, the error is:

root@bod:/# do-release-upgrade -d
Checking for a new Ubuntu release
Get:1 Upgrade tool signature [933 B]
Get:2 Upgrade tool [1165 kB]
Fetched 1166 kB in 0s (0 B/s)
authenticate 'quantal.tar.gz' against 'quantal.tar.gz.gpg'
exception from gpg: GnuPG exited non-zero, with code 2
Debug information:

gpg: Signature made Fri Sep 28 01:55:55 2012 UTC using DSA key ID 437D05B5
gpg: /tmp/update-manager-xWzlHA/trustdb.gpg: trustdb created
gpg: Good signature from "Ubuntu Archive Automatic Signing Key <email address hidden>"
gpg: WARNING: This key is not certified with a trusted signature!
gpg: There is no indication that the signature belongs to the owner.
Primary key fingerprint: 6302 39CC 130E 1A7F D81A 27B1 4097 6EAF 437D 05B5
gpg: Signature made Fri Sep 28 01:55:55 2012 UTC using RSA key ID C0B21F32
gpg: Can't check signature: public key not found

Authentication failed
Authenticating the upgrade failed. There may be a problem with the network or with the server.

Once the version of the keyring from precise-proposed is installed, it works fine.