Class names in PHP are case insensitive. The following two are equivalent:

class Something extends BaseClass {}

and

class someThing extends baseClass {}

However…

If you are using an autoloader that searches for a class file when the class is required, the autoloader will match the file based on the filesystem’s case-sensitivity. This caught me out because I develop on a Mac which is case-aware but not case sensitive. When I deployed some code to a Linux server I discovered I had a class which … extends view rather than … extends View. The autoloader found the file (View.php) on my dev machine but the remote server was looking for view.php, couldn’t find it and erorred out.