According to this post on the PHP-GTK Community site, the latest version of the software, PHP-GTK 2.0.1, has been released.

This release, named you knew this was coming, adds full support for GtkBuilder and tooltips; in addition to a slew of bug fixes and overrides. [...] Coming up next: Akshat Gupta, our student for the Google Summer of Code program this year, will be working on cairo support for PHP-GTK.

The post also lists the changes to the packages included (and excluded) with this new release.