There is a updated version of the php sdk.
In this update, the public function useFileUploadSupport() has been rename as getFileUploadSupport(). This function is used to check whether the PHP SDK is currently configured for supporting file upload.
The original function useFileUploadSupport is now marked as deprecated. So, there should not be any code changes required if you are to upgrade the PHP SDK in your Facebook canvas app / website. Having said that, it would be best for you to do a global search-and-replace when performing the upgrade.