Especially if you are using Windows
The main system for development and testing, most of the functionality is first implemented here, then implementation on other platforms. This version can work in regular, server and portable mode (see settings page).
Especially if you are using Mac OS
This version comes as a bundle, you need to pass the command line parameters directly to the executable file
Especially if you are using Linux
This version means working only in server mode, without icons in the taskbar and other things. To access the GUI possible with a modern browser. Configuration is done via command line parameters (recommended) or via config.ini. You can access the server from another computer, for example