After dist-upgrade to 14.04 I get "You don't have permission to access /wiki/ on this server." for a MediaWiki installation with alias. /w/index.php
is also failing.
So far I have seen a difference in configuration between 12.04 and 14.04 and I did
cd /etc/apache2/sites-available
sudo ln -s ../sites-available/000-default.conf .
This fixed other problems, but not the MediaWiki problem.
This is an issue with a missing link:
This made the wiki instance appear again.
Another error appeared after fixing the initial problem. This was due to change in MediaWiki database schema (if I understand correctly). I solved this with:
As far as I can determine the wiki is now running ok.