Please review the following article to determine if PHP 5.5 can be enabled on your specific hosting account:
PHP 5.5 for Linux Shared and Reseller Hosting
PHP 5.5 is available on all Linux Shared and Reseller hosting accounts by navigating to the PHP Configuration icon in the Advanced section of your cPanel. For additional information regarding this plugin please refer to the following article:
PHP 5.5 for VPS and Dedicated Servers
For VPS with cPanel and Linux Dedicated Servers, HostGator offers the latest stable version of PHP 5.5. Currently, PHP 5.5.8 or higher is available. Please contact HostGator for additional details.