Porcupine is available open-source under the LGPL license. It requires an existing web server installation and a web connector. Currently it supports Apache with MOD_PYTHON or any other web server that is WSGI or CGI enabled.
The latest official version is 0.6. If you already have Python installed then you can download the Porcupine source:
Alternatively, there is also Windows installer which does not require Python to be preinstalled:
Upgrading Porcupine is only supported for two consequent official releases. The following downloads offer upgrade packages from release 0.5.2 to 0.6:
Download porcupine-upgrade-0.6-src.zip source upgrade, or alternatively if you are using the Windows installer,
Visit the Porcupine upgrade instructions wiki page for step-by-step instructions.
Grab the latest development version from my github repository:
$ git clone git://github.com/tkouts/porcupine.git
Next, don't forget to initialize the Porcupine database by typing:
$ python ./db_init.py
You can download previous Porcupine releases from sourceforge.