The LINUX development is indefinitely on hold. There are a few reasons for this:
1. GTK+ for Windows was not working well enough (not stable) and was causing ATTAC to freeze.
2. Since more users use windows than linux, not everyone liked the linux "look" to the GUI.
3. making ATTAC work with LINUX and windows is not easy and i am only one person.
From all the reasons above, i decided to continue with the windows version only. in the event that GTK+ becomes stable for windows, i might reconsider the linux version. The LINUX version (v4 BETA 3) is availale for download if you like from the ATTAC website but i make no guarentees and i will not be fixing bugs in the LINUX version:
http://www.tw-attac.com/downloads/old/
earth.