Ah, for precise the key signing date was wrong. Tried it again with the same results.
(precise2-amd64)root@impulse:/home/bdmurray/source-trees/ubuntu-archive-tools/upstream# gpg --list-packets /tmp/update-manager-TEgnXk/trusty.tar.gz.gpg :signature packet: algo 17, keyid 40976EAF437D05B5 version 4, created 1480546800, md5len 0, sigclass 0x00 digest algo 2, begin of digest 3b 37 hashed subpkt 2 len 4 (sig created 2016-11-30) subpkt 16 len 8 (issuer key ID 40976EAF437D05B5) data: [158 bits] data: [159 bits] -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1645906 Title: new dist-upgrader tarballs necessary so they are signed with 4k key To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/ubuntu-release-upgrader/+bug/1645906/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs