Some configuration parameters have changed in Apache 2.4. I had a similar issue when I was setting up a Zend Framework 2 application. After some research, here is the solution:
Incorrect Configuration
ServerName zf2-tutorial.localhost
DocumentRoot /path/to/zf2-tutorial/public
SetEnv APPLICATION_ENV "development"
DirectoryIndex index.php
AllowOverride All
Order allow,deny #<-- 2.2 config
Allow from all #<-- 2.2 config
Correct Configuration
ServerName zf2-tutorial.localhost
DocumentRoot /path/to/zf2-tutorial/public
SetEnv APPLICATION_ENV "development"
DirectoryIndex index.php
AllowOverride All
Require all granted #<-- 2.4 New configuration
If you are planning to migrate from Apache 2.2 to 2.4, here is a good reference: http://httpd.apache.org/docs/2.4/upgrading.html