I have it running on a Plesk 12.5 sever, MariaDB 10, PHP 7 as a Plesk option in hosting, works EXCELLENT (after all the install issues and heartaches). But for those instances I need to do things in SSH, I can't. And I'm guessing chron jobs will fail too.
I do NOT want to try to upgrade PHP server-wide, for fear of destroying Plesk or other things.
Re: PHP Version 5.5 on Centos server, but hosting multiple PHP versions for Plesk.
You should be able to setup a separate PHP handler with a different PHP version and if you are using Apache or similar web server (including LiteSpeed), you can add the handler to your .htaccess file and anything within the directory will use the different PHP version.