Old version of PHP framework Yii.
Yii is a generic Web programming framework, meaning that it can be used for developing all kinds of Web applications using PHP. Because of its component-based architecture and sophisticated caching support, it is especially suitable for developing large-scale applications such as portals, forums, content management systems (CMS), e-commerce projects, and so on.
Yii 1 is the first version of the Yii framework. Yii 1.0 was released in December 2008 and it is no longer supported. Yii 1.1 was released in January 2010 and reached the end of life in November 2015. Since then it only receives security bugfixes and fixes that improve compatibility with new versions of PHP. In October 2014 the successor of Yii 1.1 was released: yii2.
Official documentation can be found in the Definitive Guide to Yii 1.1. Further important resources: