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 major versions of Yii: 2.0 and 1.1.

Yii 2.0

The latest version of Yii 2 is 2.0.3, released on March 1, 2015. 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.

There are two ways to install Yii 2: using Composer, or downloading an application template. We highly recommend you to use the former.

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.

After installing Composer, run the following command to install the Composer Asset Plugin:

php composer.phar global require "fxp/composer-asset-plugin:1.0.0"

Now choose one of the application templates to start installing Yii 2.0. An application template is a package that contains a skeleton Web application written in Yii.

  • To install the basic application template, run the command below:
    php composer.phar create-project yiisoft/yii2-app-basic basic 2.0.3
  • To install the advanced application template, run the command below:
    php composer.phar create-project yiisoft/yii2-app-advanced advanced 2.0.3

Note that you may be prompted to enter your GitHub username and password during the installation process. This is normal. Just enter them and continue.

Install from an Archive File

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

Upgrade from Older Versions

If you are upgrading from Yii 2.0.0 with composer, simply run the following command in your project's root directory:

php composer.phar require yiisoft/yii2 2.0.3

If you installed Yii using an archive file, you should download the new release file, extract it and replace the older version with the new one.

Upgrading from Yii 1.1 is not trivial. Please refer to the guide about upgrading from Yii 1.1.

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.

Yii 1.1

Yii 1.1 is currently under maintenance mode. 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 1.1.16 (Dec 21, 2014)
Status Stable
Source Code yii-1.1.16.bca042.tar.gz (.zip file)
change log, upgrade instructions
Documentation yii-docs-1.1.16.bca042.tar.gz (.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