This is documented for the benefit of others. Hopefully Google indexes this.
If during upgrade, apt fails and complains leaving you in inconsistent state (this happened for me with texlive cyclical dependencies), try looking at the dpkg message.
I got an error in dpkg where it would refuse to install a package upgrade since it would overwrite a file included in an older version of another package. This was fixed by using dpkg manually and forcing it. Then apt-get -f install was run to continue fixing.
After multiple rounds of apt-get upgrade, apt-get dist-upgrade until no packages were left, there were still many parts of the system that said 17.3 Rosa.
Additionally, many gnome apps were installed giving a very bad experience. Furthermore, things like the system .bashrc (e.g. colored prompt) did not work.