This is due to the blender PPA that you have enabled which provides python packages with version numbers greater than those in Trusty. The release upgrader will not downgrade those packages so the upgrade process quits. You'll need to use a tool like ppa-purge to remove the problematic (irie-blender-saucy) PPA.
** Changed in: ubuntu-release-upgrader (Ubuntu) Status: New => Invalid -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1364362 Title: Update from 13.10 to 14.04 fails To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/ubuntu-release-upgrader/+bug/1364362/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs