The source code of this extension, and binaries for Windows are hosted by » github,
Fetching the source code and building the extension:
git clone https://github.com/krakjoe/wkhtmltox cd wkhtmltox phpize ./configure --with-wkhtmltox=/path/to/wkhtmltox/installation make sudo make install
Fetching updates and rebuilding the extension:
cd wkhtmltox phpize --clean git pull origin master phpize ./configure --with-wkhtmltox=/path/to/wkhtmltox/installation make sudo make install