Mac OSX platform :

• Growl requires Mac OS X 10.5 or higher.

Windows platform :

• Growl for Windows is a Windows-compatible version of Growl, a notification system for Mac OS X.

Mandatory resources :

• PHP 5.2.0 or newer
• pcre extension
• SPL extension
• hash extension requires no external libraries and is enabled by default as of PHP 5.1.2

Optional resources :

• mcrypt extension when using GNTP adapter and encryt feature