Yii is an open source project released under the terms of the BSD License. This means that you can use Yii for free to develop either open-source or proprietary Web applications.

Currently there are two versions of Yii: 1.1 and 2.0.

Yii 1.1

Yii 1.1 is the latest stable version. You may safely use this version in your production Web applications. Continued support and bug fixes for this version will be provided until December 31, 2015 or further if needed.

  Yii Framework 1.1.x
Latest Release 1.1.15 (Jun 29, 2014)
Status Stable
Source Code yii- (.zip file)
change log, upgrade instructions
Documentation yii-docs- (.zip file)
Requirement PHP 5.1.0 or above
End of Maintenance Dec 31, 2015 (may be extended further if needed)
Release History download archived releases
Git Access

You can obtain the latest development version of Yii from GitHub repository using the following URL:
SVN Access

You can also obtain the latest Yii source code via SVN using:

svn checkout yii

Yii 2.0

The latest version of Yii 2 is 2.0.0 beta, released on April 13, 2014.

Yii 2.0 is a complete rewrite of Yii on top of PHP 5.4.0. It is aimed to become a state-of-the-art of the new generation of PHP framework. Yii 2.0 is not compatible with 1.1.

Yii 2.0 is not ready for production use yet. It is currently under heavy development and we may introduce significant changes without prior notices. You may consider using Yii 2.0 if you just start to learn Yii or you do not have a tight project schedule.

Yii 2.0 is released in terms of application templates. Each application template is a skeleton Web application built on Yii 2.0 and is ready to use out of box. We currently provide two application templates: the basic application template and the advanced application template.

Install via Composer

This is the preferred way of installing Yii 2.0. If you do not have Composer yet, you may install it by following the instructions here.

To install the basic application template, run the command below:

php composer.phar create-project yiisoft/yii2-app-basic basic 2.0.0-beta
To install the advanced application template, run the command below:
php composer.phar create-project yiisoft/yii2-app-advanced advanced 2.0.0-beta

Install from an Archive File

Download one of the following archive files, and then extract it to a Web-accessible folder:

Obtain the Latest Code

Yii 2.0 is hosted on GitHub. You are welcome to contribute to the Yii 2.0 development by submitting issue reports or merge requests.