Frecuently we need to upgrade or downgrade php version, in most cases it has to be configure throught php.ini file, but it is only accesible via SSH connection or only you are not able to do it.
There is a simple way to incorporate this change in server, you could use .httaccess file, use the follow line. (htaccess file has to be setted in aprpropriate folder, in which you need to modify php version), in this case in whole project like (public_hmtl)
AddHandler application/x-httpd-php56 .php