Here are a few articles that mention it:

https://documentation.cpanel.net/display/EA/Custom+Modules
https://forums.cpanel.net/threads/how-to-easy-php4-php5-side-by-side-after-removal-of-php4-from-easyapache.304942/
http://www.liquidweb.com/kb/the-end-of-php-4/
https://www.siteground.com/kb/how_to_have_different_php__mysql_versions/

You can set the handler for the site using a .htaccess file in the domains webroot with the following contents:
Code:
AddHandler application/x-httpd-php4 .php .php4 .php3