This is a list of notable software packages which were published under a proprietary software license but later released as free and open-source software, or into the public domain.
In some cases, the company continues to publish proprietary releases alongside the non-proprietary version.
+List of formerly proprietary and closed-source software Title Original release Relicensed release Initial free relicense Notes 3D Movie Maker 1995 2022 MIT The source code and assets for entire program (minus fonts) was uploaded to GitHub on 4 May 2022, under the MIT License. Adobe Flex 2004 2007 MPL-1.1 Since renamed to Apache Flex and changed to Apache-2.0 AdvFS 1990s 2008 GPL-2.0-only HP opened up AdvFS from Tru64 UNIX. AOLserver 1999 GPL / modified MPL Apache Derby 1996 2004 Apache-2.0 Relational database management system originally called Cloudscape; released as free and open-source software by IBM in 2004 and donated to the Apache Software Foundation Apache Wave 2009 2009 Apache-2.0 Formerly Google Wave. Apus Game Engine 2008 2020 BSD-3-Clause Released to the public by the developer after reaching a Patreon goal. The source code for Astral Heroes (one of the games using the engine) was released to patrons. Astrolog 1991 2015 GPL-2.0-or-later / custom permissive Has always been freeware and open source, but had a custom attribution demanding permissive license. Atom 2014 2014 MIT BASIC Computer Games 1973 2021 Public-domain software (Unlicense) On 31 December 2021, Jeff Atwood published an updated version of the 101 games included in the original BASIC Computer Games on GitHub under the Unlicense, with permission of David H. Ahl. On 15 June 2022, Ahl formally released everything he had ever written or edited, from prose to software, into the public domain; which includes titles like More BASIC Computer Games and BASIC Computer Adventures. BDS C Compiler 1979 2002 Public domain Released by author BitKeeper 2000 2016 Apache-2.0 Bitstream Vera (font) 2003 custom Through the efforts of Bitstream and the GNOME FoundationBlades of Exile 1997 2007 CPL-1.0 Relicensed to the GPL-2.0-only at some point between 14 May 2007 and 12 June 2007. Blender 1996 2003 GPL-2.0-or-later BlitzBASIC (Blitz3D, BlitzPlus, BlitzMax) 2001 2014 Zlib BlitzPlus was released as open source on 28 April 2014 under the Zlib license on github.com.BlitzPlus Source Code Released by simonh (2014-04-29)Blitz3D open sourced! on Blitz3D Forums by (2014) Blitz3D follow on 3 August 2014.Blitz3D Now Free and Open Source! by simonh (2014-08-03)blitz3d on github.com BlitzMax was open sourced on 21 September 2015.blitzmax on github.com BRender 1995 2022 MIT Source code for 1997 and 1998 versions released under the MIT License on GitHub on 3 May 2022. The source code for 3D Movie Maker, a computer program using the engine was also released under the same license. C-Dogs 1999 2002–2016 Public-domain software/CC BY 3.0 Source code released to the public on 13 February 2002, under a public-domain-equivalent license. The graphics were re-licensed to the CC BY 3.0 license on 13 April 2016. Cafu Engine 2000 2009 GPL-3.0-or-later Originally released under the GPL-3.0-or-later license (with an option for a commercial license), in 2016 was re-licensed under the MIT license. Catacomb 1989 2014 GPL-2.0-or-later Catacomb II 1991 2014 GPL-2.0-or-later Catacomb Abyss 1992 2014 GPL-2.0-or-later Catacomb Armageddon 1992 2014 GPL-2.0-or-later Catacomb 3D 1991 2014 GPL-2.0-or-later C*Base 1980s 2003 GPL-2.0-or-later Cemu 2015 2022 MPL-2.0 Source code released under the Mozilla Public License 2.0 on 24 August 2022. Command & Conquer: Renegade 2002 2025 GPL-3.0-or-later Command & Conquer: Generals – Zero Hour 2003 2025 GPL-3.0-or-later Command & Conquer 3: Tiberium Wars 2007 2025 GPL-3.0-or-later Command & Conquer 3: Kane's Wrath 2008 2025 GPL-3.0-or-later Command & Conquer: Red Alert 3 2008 2025 GPL-3.0-or-later Command & Conquer: Red Alert 3 – Uprising 2009 2025 GPL-3.0-or-later Command & Conquer 4: Tiberian Twilight 2010 2025 GPL-3.0-or-later ChakraCore 2009 2016 MITOn 13 January 2016 Microsoft released ChakraCore under the MIT license on GitHub.Microsoft open sources Edge web browser's JavaScript engine, plans port to Linux on zdnet.com by Steven J. Vaughan-Nichols (on 2016-01-13) ChakraCore is essentially the same as the Chakra engine that powers the Microsoft Edge browser, but with platform-agnostic bindings, i.e. without the specific interfaces utilised within the Windows Universal App platform. CMU Sphinx 2000 Custom BSD-style license CodeXL 2016 MIT Coherent 1980 2015 BSD-3-Clause CP/M family 1974 1997, 2001, 2014 CuneiForm 1993 2008 BSD-3-Clause Optical character recognition software Dagor Engine 2003 2023 BSD-3-Clause Gaijin Entertainment's in-house game engine was quietly released on GitHub under a BSD license in 2023; this open-source release will be used as the base for VK's Nau Engine. Dink Smallwood 1998 2003 zlib-like Some game data (e.g. sounds) not released under a free license. DOS.MASTER end 1980s 2000 Public-domain software DOS.MASTER is a program for Apple II computers which allows Apple DOS 3.3 programs to be placed on a hard drive or 3.5-inch floppy disk and run from ProDOS. Written by Glen Bredon as a commercial program during the late 1980s, it was released into the public domain by his family after the author's death.Public.Domain.notice.txt on apple2.org.za Duke Nukem 3D 1996 2003 GPL-2.0-or-later Game code only, no data, no engine. Elasticsearch 2021 2024AGPL-3.0-only Originally Apache licensed; taken proprietary to pressure AWS; then added AGPL Etherpad 2008 2009 Apache-2.0 Open sourced after being purchased by Google Extensible Storage Engine 1994 2021 MIT Formerly known as JET Blue Falcon 2007 GPL FAR Manager 1996 2007 BSD-3-Clause Version 2.0 released as open source. File Manager (Windows) 1990 April 2018 MIT On 6 April 2018, Microsoft released binaries and the source code, licensed under the MIT license, for an improved version of File Manager able to be run on Windows 10. This version included changes such as the ability to compile in modern versions of Visual Studio, the ability to compile as a 64-bit application, and numerous usability improvements. Fish Fillets 1998 2002 GPL-2.0-or-later Free Download Manager 2003 2007 GPL-3.0-only Free since version 2.5Free Download Manager » Blog Archive » FDM 2.5 is released! FoundationDB 2013 2018 Apache-2.0 Apple Inc. acquired the founding company in March 2015 and discontinued downloads of the software. In April 2018, Apple open-sourced the database and resumed downloads. Game-Maker 1991 2014 MIT After some consultation with the user base, on 12 July 2014 original coder Andy Stone released the Game-Maker 3.0 source code on GitHub, under the MIT license.G. Andrew Stone, "Recreational Software Design's GameMaker product, released in 1994" GGPO 2006 2019 MIT On 9 October 2019 Cannon announced on his Twitter account that GGPO was now open source and available under the MIT license. Ghostery 2010 2018 MPL-2.0 Cliqz GmbH acquired Ghostery from Evidon, Inc. in February 2017. Ghostery's software was open-sourced on 8 March 2018. GEM family 1985 1999 GPL Development continued as OpenGEM and FreeGEM. Gentium (font) 2002 2005 OFL Through the efforts of SIL International Gigablast 2000 2013 Apache-2.0 Glitch 2011 2013 CC0 After Glitch was officially shut down on 9 December 2012, the artwork and most of the source code was released under the CC0 license on 18 November 2013. On 9 December 2014, a fan project to relaunch Glitch under the name Eleven began alpha testing. GLX 1990s 2008 SGI FreeB License GW-BASIC 1983 2020 MIT Haaf's Game Engine 2004 2005 LGPL-2.0 Originally released under the LGPL-2.0 license on 25 November 2005, the following year it was re-licensed under the Zlib license. On 7 August 2011, the source code used for the Mac OS X and Linux ports of Hammerfight was also released. Hovertank 3D 1991 2014 GPL-2.0-or-later ILWIS 1988 2007 GPL-2.0-only Released as free and open-source software by ITC. Doom engine 1993 1999 GPL-2.0-or-later The released version is the source code to Doom. Originally released under a restrictive license on 23 December 1997. The sources for Heretic and Hexen: Beyond Heretic (other two games using the Doom engine) were released under the GPL-2.0-only license. The source code for the Atari Jaguar version of Doom was released under the non-free Doom Source License. The source code for the 3DO Interactive Multiplayer port of Doom was released under the MIT License. Quake engine 1996 1999 GPL-2.0-or-later The released version is the source code to Quake. The map sources were also released under the GPL in 2006. In 2000 the source for Hexen II (another game using the id Tech 2 engine) was released under the GPL-2.0-only license. id Tech 2 1997 2001 GPL-2.0-or-later The released version is the source code to Quake II. id Tech 3 1999–2001 2005–2010 GPL-2.0-or-later The released version is the source code to Quake III Arena. The source code for other id Tech 3 games, such as Star Wars Jedi Knight II: Jedi Outcast, and Star Wars Jedi Knight: Jedi Academy was also released.An updated version of the engine was released in 2010 under the GPL-3.0-or-later license. The released version is the source code to Return to Castle Wolfenstein and Wolfenstein: Enemy Territory. id Tech 4 2004–2012 2011–2012 GPL-3.0-or-later The released version is the source code to Doom 3. Changes to the code had to be made to avoid use of the patented Carmack's Reverse.