The main PHP 6 feature is native Unicode support, which is currently being implemented. Consequently, a lot of work still has to be done to deliver a full native Unicode support. At the moment, the work of updating all the functions in php-src is roughly 60% complete. In order to speed up the process, the decided approach was to use the ICU library (International Components for Unicode).

The main goal of this project is to complete the update of the functions in php-src. The update will consist basically of data type checking. All the parameter parsing has to be ported to use the Unicode methods and the operations over the incoming data have to be consistent with its type. In addition, they also have to return the correct values. In order to achieve this, ICU macros and functions are used to handle Unicode encoded strings properly.