"When we chose Symfony to implement ThemBid.com, PHP 5 was needed but we only had PHP 4 installed in our Ubuntu hosting servers. We couldn't just migrate everyone to PHP 5 since some of client's applications were incompatible with PHP 5. Some tutorials were found online explaining how to run PHP 4 and PHP 5 simultaneously such as this and this but they all used CGI. As you probably know, CGI is not scalable and we needed to scale in PHP4 and PHP5 since we needed to server millions of hits in both configurations..."
