CakePHP 2.0 has been re-factored and rebuilt with many internal and external API changes. It uses native PHP5 features, updated conventions for class and file names, and a new loader. Exceptions replace the old error handling. Collections unify how helpers, components, behaviors and tasks are loaded and used. The console, request/response, sessions, authentication, email, and testing have all been improved for better performance and extensibility. Benchmarks show CakePHP 2.0 has significantly better performance than 1.3.11.