List of formerly proprietary software
This is a list of notable software packages which were formerly published under a proprietary software license but were subsequently released as free or open source software (as defined by the Free Software Foundation and Open Source Initiative, respectively).
Though formal free and open source software licenses have existed since the early 1980s, since that time most retail software packages have been released under proprietary, binary-only licenses. The popularization of GNU/Linux and other free software packages in the mid- to late 1990s incited some companies to "liberate" their software by rereleasing it under less restrictive terms. Netscape's much-publicized liberation of its web browser suite in 1998 is believed to have started this trend.
In some cases, the company continues to publish a proprietary, binary-only alongside the liberated version.
| Title | Original release | Free release | Free license | Notes |
|---|---|---|---|---|
| Netscape Navigator/Communicator | 1994 | 1998 | MPL | see Mozilla |
| Doom | 1993 | 1999 | GPL | source released under a non-free license in 1997 |
| Quake | 1996 | 1999 | GPL | |
| Qt | 1991 | 1999 | QPL | |
| StarOffice | 1986 | 2000 | LGPL/SISSL | free version released as OpenOffice (later OpenOffice.org) |
| Quake II | 1997 | 2001 | GPL | |
| Rise of the Triad | 1994 | 2002 | GPL | |
| C*Base | 198? | 2003 | GPL | |
| Duke Nukem 3D | 1996 | 2003 | GPL | |
| Watcom C Compiler | 1988 | 2003 | Open Watcom Public License | free version released as OpenWatcom |
| Solaris | 1989 | 2005 | CDDL | free version released as OpenSolaris |
| Quake III Arena | 1999 | 2005 | GPL | |
| Marathon 2: Durandal | 1995 | 2000 | GPL | now known as Alephone |
| Gentium | 2002 | 2005 | OFL | http://scripts.sil.org/] |