Running through the typical upgrade steps.
$ sudo apt-get update $ sudo apt-get dist-upgrade $ sudo do-release-upgrade -d
However, upgrade seems to fail due to broken packages, see below. Most likely due to many legacy PPA added for certain kind of special packages.
Calculating the changes Could not calculate the upgrade An unresolvable problem occurred while calculating the upgrade. This can be caused by: * Upgrading to a pre-release version of Ubuntu * Running the current pre-release version of Ubuntu * Unofficial software packages not provided by Ubuntu
Found the answer to troubleshot this issue. You must keep the upgrade running at the same time, otherwise the `apt.log` file would not be found. I was surprised that I have so many broken and conflicting package. Follow the procedure, I have to manually remove all broken packages. For certain packages, I have to reinstall because it can't find the actual packages. Result below were truncated to save space.
$ grep Broken /var/log/dist-upgrade/apt.log Broken libdouble-conversion1:amd64 Breaks on libdouble-conversion1v5:amd64 ...... Broken imagemagick-6-common:amd64 Breaks on libmagickcore-6.q16-2:amd64 ...... Broken libgjs0f:amd64 Conflicts on libgjs0e:amd64 < 1.46.0-1 @ii mK > ......
Upgrade was slow as I've just installed LaTeX few days back. Downloading all those `texlive-` packages going to take some times.