php5 ?

[eluser]cahva[/eluser]
There were lots of changes from PHP version 5.2 -> 5.3. Some of those changes(like removing deprecated functions etc.) made CI not to work with PHP 5.3. Lots of hosts use still PHP 5.2.x on their servers because 5.3 "broke" lots of old apps.

CI itself doesnt take advantage of PHP 5, but that does not mean that you cant.