Is it easy (or not so) to add a PHP version >=5.4 to ISPManager 4?

Question

PHP

Issue/Conflict :
Server admin doesn't want to update PHP to version >=5.4

This is not possible as 5.4+ drops support for many features that are used by client sites. In 5.4 they are just deprecated

I understand him.
But on this server I will need to place the production version of the project being developed.
And PHP 5.4 required.
In ISPManager 5 - the issue of adding other versions of PHP is solved very quickly, through the interface. (he solved it on his dev server)
And what about ISPManager version 4?
Is it easy (or not so) to add a PHP version >=5.4 to it?
OS FreeBSD
Ruta I have, of course - no.
I know very little about administration.
I am writing in a hurry because project deadlines are running out.
Google did not give anything sensible (but if I was just not attentive - sorry)
In any case, I will be grateful for any help.

Answer 1

without root ssh in any way, here is the answer from IspSystem why
and with it you can compile from the sources and make the desired version included, for example, by choosing the cgi mode for the domain

Answer 2

firstwiki.ru/index.php/%D0%A1%D0%BC%D0%B5%D0%BD%D0...

Answer 3

In short, your sysadmin is right.