Apache forgots about configurations

After upgrading Ubuntu 13.04 to 13.10 I received a new Apache (2.4). In the base configuration it now only looks for (example) sites with configuration files ending with .conf. It is not a bad thing but if you earlier (as I) did not have that extension my sites were not configured.

It is easy to solve. Just add .conf to the name of the configuration files and restart apache. Now it should work.