When upgrading to Tor 0.2.4.19-1~d79.jessie+1 (using sudo apt-get dist-upgrade), your Tor connection may go down. There is a temporary workaround.
In /etc/default/tor near bottom comment in (by removing the # in front of it).
sudo service tor restart
You should keep that in mind and undo that change when Whonix or Tor fixes that bug. We'll keep you posted.