The current version of RAT4 is available for download in binary form for Linux and WinXP. The license for this version is  open source, specifically using a BSD style license.

Source code for all versions (including the older version 3) and the current development version are available from this Subversion repository.

Version: Build Date Release Type Binaries (and source tgz) Changes
4.4.01 12th February 2008 Stable Windows XP Linux,OSX,src  Changes
4.3.00 13th September 2006 Stable Windows XP Linux(fedora4, glibc2.4),OSX,src  Changes
4.2.27 12th April 2006 Developer Windows XP Linux(fedora4, gentoo-gcc345),src  Changes
4.2.25 12th January 2004 Stable  4.2.25  Changes

Old RAT Version 3 Toll Quality Audio Release

Version Release Date Source and Binaries(Solaris, SunOS4, Irix 6.2, Linux, FreeBSD, Windows, NetBSD)
3.0.35 September 1999  3.0.35