The most common configuration for Apache and PHP uses mod_php, but this only allows a single PHP version. Apache httpd 2.4 introduces mod_proxy_fgci which can simply redirect requests to a php-fpm backend.
This article shows a simple way to use a single Apache server and simultaneously run 3 versions of PHP (5.3, 5.4 and 5.5). The same site will be served through 3 sub-URL.
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