Thank you for choosing Yii 2 - a modern PHP framework designed for professional Web development.

Yii 2 is a complete rewrite of its previous version Yii 1.1 which is one of the most popular PHP frameworks. Yii 2 inherits the main spirit behind Yii for being simple, fast and highly extensible. Yii 2 requires PHP 5.4 and embraces the best practices and protocols found in modern Web application development.

build/               internally used build tools
docs/                documentation
framework/           core framework code
tests/               tests of the core framework code

The minimum requirement by Yii is that your Web server supports PHP 5.4.

Yii 2.0 has a Definitive Guide and a Class Reference which cover every detail of Yii.

There is also a PDF version of the Definitive Guide and a Definitive Guide Mirror which is updated every 15 minutes.

For 1.1 users, you may refer to Upgrading from Yii 1.1 to have a general idea of what has changed in 2.0.

Your participation to Yii 2 development is very welcome!

You may participate in the following ways:

• Report an issue
• Translate documentation or messages
• Give us feedback or start a design discussion
• Contribute to the core code or fix bugs