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 2.0.14, released on February 19, 2017. Yii 2.0 is a complete rewrite of Yii on top of PHP 5.4.0 as a minimum requirement and fully compatible with PHP 7.x. It is aimed to be 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.

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 2.0.14
  • To install the advanced application template, run the command below:
    php composer.phar create-project yiisoft/yii2-app-advanced advanced 2.0.14

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 commands in your project's root directory:

First, make sure you have the latest version of the Composer Asset Plugin:

php composer.phar global require "fxp/composer-asset-plugin:^1.2.0"

Then upgrade Yii by running:

php composer.phar update yiisoft/yii2 yiisoft/yii2-composer bower-asset/jquery.inputmask

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 has ended on December 31, 2016. Security fixes will be provided until December 31, 2019.

  Yii Framework 1.1.x
Latest Release 1.1.19 (June 8, 2017)
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, 2016
Security support until Dec 31, 2019 (may be extended further if needed)
Release History starting from version 1.1.14: release history on Github
until version 1.1.13: download archived releases from Google Code
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