Apache2.4 - PHP 5.6 and PHP7.1 running at the same time

Question

I'm looking to run both PHP 5.6 and 7.1 in my development server, with Apache. I know that Nginx can easily handle this, but I really need Apache.

Here so confs

# My main configuration file, running with PHP7.1

<VirtualHost xx.xx.xx.xx:80>
    ServerName www.mydomain.com
    ServerAlias mydomain.com

    DocumentRoot /var/www/mydomain.com/html
</VirtualHost>

<VirtualHost xx.xx.xx.xx:80>
    ServerName xx.xx.xx.xx

    <Directory />
        Deny from all
    </Directory>
</VirtualHost>


# PHP 5.6

<VirtualHost xx.xx.xx.xx:80>
    ServerName foo.mydomain.com

    DocumentRoot /var/www/foo.mydomain.com/html

    <FilesMatch \.php$>
        SetHandler "proxy:unix:/var/run/php/php5.6-fpm.sock"
    </FilesMatch>
</VirtualHost>

The 7.1 is working, while 5.6 returns a 404. Thanks !