Due to the upgrades my pkgdb.db file became unrecognizable halfway during execution of the portupgrade -a command so I had to do a rm /usr/ports/INDEX-6.db and a rm /var/db/pkg/pkgdb.db and finally a portupgrade -a again to make everything right.
On top of that my mousewheel seems to have ceased working again so that probably means a good few hours of experimenting with all kinds of esoteric programs and parameters until the magic combination for my particular setup is found – I can’t wait…