In general we like to upgrade to the latest stable php version when its released.
To check the version of php on your hosting account, do the following:
1) create a file called testphp.php
2) In the file you created, put the following code and nothing else.
3) upload the file to your server with ftp or file manager
4) browse to the page on your server via a web and all the details about php will be shown.
If you have any doubts, please submit a support ticket.