This fixed the issue.
Thank you so very much, for the quick and high quality, late night, replies! :-)
There's only one question left: How can I get back to current branch, after reverting to the previous version?
Just in case I am going wild and upgrade raspbian to stretch in the near future.
/tldr: sudo nano /etc/resolv.conf (change the nameserver to your router's IP) and then apply the fix as described here.