ubuntu 14.04 is a big upgrade. upgrading also affects LAMP. It comes with php 5.5 and apache 2.4
The most headache part is apache 2.4. It no longer work out of the box.
The biggest change is that in the vhost directive, you have to add
“Require all granted” in place of
Order allow,deny Allow from all
The mod-rewite is also not turned on by default. remember to