Symfony 1.4 requires PHP 5.5 or less, so it doesn't run on any current Ubuntu which ships with newer PHP versions. I don't want any old version running on my system, but still be able to maintain some legacy applications. There is a nice Docker image which does this trick: https://codeyourdream.com/blog/how-run-multiple-php-versions-apache-one-linux-machine-using-docker
Existing applications can be accessed by their local URL (the docker image uses the host's apache virtual host configurations), but on different ports depending on the PHP version needed, for example http://ondorierp.localhost:8055 for PHP 5.5. It uses the host's MySQL, which needs to be configured to use the Docker IP address to bind to.