Multi PHP version and old MySQL PHP

Hi, I got two version of PHP in my installation 7.0 and 5.6 both works with mysqli php extension but old mysql not work :
mod_fcgid: stderr: PHP Fatal error: Call to undefined function mysql_connect()
how its is possible to enable support of old mysql_* for 5.6 PHP ? I do not want rewrite some old apps to use new mysqli ..

Thanks.

 

I was follow this manual : https://www.howtoforge.com/tutorial...#nbspcompilenbspphpnbsp-as-phpfpm-and-fastcgi