As we look to improve the stability and speed of Hotaru CMS, we need to add features that are not available in older versions of PHP. In particular we are looking to add features that require at least PHP version 5.3
Can you tell us what version you currently have?
If you are not sure, go to your Admin Dashboard, turn on debug and then look at the bottom of one of your sites pages in the browser. The PHP Version and MySQL version should be listed there. You can turn debug off again afterwards.