OS is installed on a separate server, I use cron on staff activity too (I could never get the cron running properly)
To find the PHP version on your servers create a new text doc and name is 'info.php' file.
Make the first line read:
<?php phpinfo(); ?>
Save the file then open the info.php file in your browser...
Mine works as is, though I would post anything that could help other people :)