just tried do-release-upgrade

[Phil]

Everything goes nice, upgrade tool warns me about doing the upgrade over SSH, sets a reserve SSH port, downloads all the packages information and aborts on "calculating upgrade".

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: ubuntu-release-upgrader-core 1:0.220.9
ProcVersionSignature: Ubuntu 3.13.0-106.153-generic 3.13.11-ckt39
Uname: Linux 3.13.0-106-generic x86_64
NonfreeKernelModules: nvidia
ApportVersion: 2.14.1-0ubuntu3.23
Architecture: amd64
CrashDB: ubuntu
Date: Fri Dec 23 19:29:07 2016
InstallationDate: Installed on 2013-08-06 (1235 days ago)
InstallationMedia: Ubuntu 13.04 "Raring Ringtail" - Release amd64 (20130424)
PackageArchitecture: all
SourcePackage: ubuntu-release-upgrader
Symptom: ubuntu-release-upgrader
UpgradeStatus: Upgraded to trusty on 2016-12-23 (0 days ago)
VarLogDistupgradeAptclonesystemstate.tar.gz: Error: command ['pkexec', 'cat', '/var/log/dist-upgrade/apt-clone_system_state.tar.gz'] failed with exit code 127: Error getting authority: Error initializing authority: Error calling StartServiceByName for org.freedesktop.PolicyKit1: GDBus.Error:org.freedesktop.DBus.Error.Spawn.ExecFailed: Failed to execute program /usr/lib/dbus-1.0/dbus-daemon-launch-helper: Success