phpBB class name lookups follow these rules: - All classes are prefixed with phpbb_ - All classes reside in includes/ or a subdirectory thereof - Directories must not contain underscores - The class name is separated into parts by underscores, the parts are checked from first to last, until one is found which is not a directory, all remaining parts make up the file name. If no parts are left, the last directory name is used. Examples: directory structure: includes/ class_name.php dir/ class_name.php dir.php subdir/ class_name.php lookups: phpbb_class_name -> includes/class_name.php phpbb_dir_class_name -> includes/dir/class_name.php phpbb_dir -> includes/dir/dir.php phpbb_dir_subdir_class_name -> includes/dir/subdir/class_name.php Optionally the class can be supplied with a cache instance, either in the constructor or via set_cache() at a later time. This allows for the lookups to be cached, so the directories do not have to be traveresed on every request. This makes it necessary for the cache and its dependency to continue to be loaded the old way - without autoloading. The code will not be changed to use autoloading, but it will rather only be used for new classes where applicable. PHPBB3-9682