更新日志如下： 不再支持 PHP 5.1.6 Changed filenaming convention (class file names now must be Ucfirst and everything else in lowercase). Changed the default database driver to 'mysqli' (the old 'mysql' driver is DEPRECATED). $_SERVER['CI_ENV'] can now be set to control the ENVIRONMENT constant. Added an optional backtrace to php-error template. Added Android to the list of user agents. Added Windows 7, Windows 8, Windows 8.1, Android, Blackberry, iOS and PlayStation 3 to the list of user platforms. Added Fennec (Firefox for mobile) to the list of mobile user agents. Ability to log certain error types, not all under a threshold. Added support for pem, p10, p12, p7a, p7c, p7m, p7r, p7s, crt, crl, der, kdb, rsa, cer, sst, csr Certs to mimes.php. Added support for pgp, gpg, zsh and cdr files to mimes.php. Added support for 3gp, 3g2, mp4, wmv, f4v, vlc Video files to mimes.php. Added support for m4a, aac, m4u, xspf, au, ac3, flac, ogg, wma Audio files to mimes.php. Added support for kmz and kml (Google Earth) files to mimes.php. Added support for ics Calendar files to mimes.php. Added support for rar, jar and 7zip archives to mimes.php. Updated support for xml ('application/xml') and xsl ('application/xml', 'text/xsl') files in mimes.php. Updated support for doc files in mimes.php. Updated support for docx files in mimes.php. Updated support for php files in mimes.php. Updated support for zip files in mimes.php. Updated support for csv files in mimes.php. Added Romanian, Greek, Vietnamese and Cyrilic characters in application/config/foreign_characters.php. Changed logger to only chmod when file is first created. Removed previously deprecated SHA1 Library. Removed previously deprecated use of $autoload['core'] in application/config/autoload.php. Only entries in $autoload['libraries'] are auto-loaded now. Removed previously deprecated EXT constant. Updated all classes to be written in PHP 5 style, with visibility declarations and no var usage for properties. Added an Exception handler. Moved error templates to application/views/errors/ and made the path configurable via $config['error_views_path']. Added support non-HTML error templates for CLI applications. Moved the Log class to application/core/ Global config files are loaded first, then environment ones. Environment config keys overwrite base ones, allowing to only set the keys we want changed per environment. Changed detection of $view_folder so that if it's not found in the current path, it will now also be searched for under the application folder. Path constants BASEPATH, APPPATH and VIEWPATH are now (internally) defined as absolute paths. Updated email validation methods to use filter_var() instead of PCRE. Changed environment defaults to report all errors in development and only fatal ones in testing, production but only display them in development. Updated ip_address database field lengths from 16 to 45 for supporting IPv6 address on :doc:`Trackback Library <libraries/trackback>` and :doc:`Captcha Helper <helpers/captcha_helper>`. Removed cheatsheets and quick_reference PDFs from the documentation. Added availability checks where usage of dangerous functions like eval() and exec() is required. Added support for changing the file extension of log files using $config['log_file_extension']. Added support for turning newline standardization on/off via $config['standardize_newlines'] and set it to FALSE by default. Added configuration setting $config['composer_autoload'] to enable loading of a Composer auto-loader. Removed the automatic conversion of 'programmatic characters' to HTML entities from the :doc:`URI Library <libraries/uri>`. Changed log messages that say a class or file was loaded to "info" level instead of "debug", so that they don't pollute log files when $config['log_threshold'] is set to 2 (debug). 详细更新内容：请点击我。 CodeIgniter 是一个简单快速的PHP MVC 框架。EllisLab 的工作人员发布了 CodeIgniter。许多企业尝试体验过所有 PHP MVC 框架之后，CodeIgniter 都成为赢家，主要是由于它为组织提供了足够的自由支持，允许开发人员更迅速地工作。 自由意味着使用 CodeIgniter 时，您不必以某种方式命名数据库表，也不必根据表命名模型。这使 CodeIgniter 成为重构遗留 PHP 应用程序的理想选择，在此类遗留应用程序中，可能存在需要移植的所有奇怪的结构。 CodeIgniter 不需要大量代码（1.6.2 版本仅为 2.8 MB，其中的 1.3 MB 是可以删除的用户文档），也不会要求您插入类似于 PEAR 的庞大的库。它在 PHP 4 和 PHP 5 中表现同样良好，允许您创建可移植的应用程序。最后，您不必使用模板引擎来创建视图 — 只需沿用旧式的 HTML 和 PHP 即可。 CodeIgniter 3.0.0 发布，不再支持 PHP 5.1.6下载地址
