Between 1992 and 1995 the project switched to UNIX (and switched the networking to TCP/IP), supporting Digital UNIX on Alpha-based systems, and Solaris on systems from Sun Microsystems. By the late 1990s it was additionally supporting Linux, and by 2005 it was supporting Red Hat Linux, Solaris, and Tru64 UNIX. It was about this time that the project open-sourced its software (using the GNU General Public License; it had previously had an `academic use only' licence), and reworked its build system so that the software could be built on a much broader range of POSIX-like systems, including OS X and Cygwin.