List of software forks

This is a dynamic list and may never be able to satisfy particular standards for completeness. You can help by expanding it with reliably sourced entries.

This is a list of notable software forks.

A timeline chart of how Linux distributions forked. The three largest trees are (from top) Debian, SLS and Red Hat.

Undated

• The many varieties of proprietary Unix in the 1980s and 1990s — almost all derived from AT&T Unix under licence and all called "Unix", but increasingly mutually incompatible. See UNIX wars.
• Most Linux distributions are descended from other distributions, most being traceable back to Debian, Red Hat or Softlanding Linux System (see image right). Since most of the content of a distribution is free and open source software, ideas and software interchange freely as is useful to the individual distribution. Merges (e.g., United Linux or Mandriva) are rare.
• Pretty Good Privacy was forked outside of the United States to free it from restrictive US laws on the exportation of cryptographic software.
• The game NetHack has spawned a number of variants using the original code, notably Slash'EM (1997), and was itself a fork (1987) of Hack.
• Openswan and strongSwan, from the discontinued FreeS/WAN.

1985

• POSTGRES (later PostgreSQL), after Ingres branched off as a proprietary project.

1990

• Microsoft SQL Server, from Sybase SQL Server, via a technology-sharing agreement concerning the Tabular Data Stream protocol.
• SWLPC, from LPMud.

1991

• Xemacs, from GNU Emacs, originally for Lucid Corporation internal needs.

1993

• FreeBSD started as a patchkit to 386BSD.
• NetBSD started as a patchkit to 386BSD.

1995

• Apache HTTP Server, from the moribund NCSA HTTPd.
• OpenBSD was a fork of NetBSD 1.0 by Theo de Raadt due to internal developer personality clashes.

1997

• EGCS was a fork of GCC, later blessed as the official version.

1998

• Grace, from Xmgr, after that project ceased development.

1999

• FilmGIMP, later called CinePaint, from GIMP, to handle 48-bit colour.
• OSSH from SSH, when that project was proprietised.
• OpenSSH, from OSSH.
• Sodipodi, from Gill.
• Steel Bank Common Lisp, from CMU Common Lisp.

2000

• TrueCrypt, from E4M when the latter was discontinued.
• Tux Racer went proprietary in 2000, leading to several forks including OpenRacer, PlanetPenguin Racer and Extreme Tux Racer.

2001

• ELinks began as an experimental fork of Links.
• Fluxbox, from Blackbox.
• GNU Radio, from pSpectra.
• Xvid was a fork of OpenDivX.
• WebKit project was started within Apple by Don Melton on 25 June 2001 as a fork of KHTML.

2002

• Beep Media Player, from XMMS, to port the program to GTK+ 2.
• GForge, from SourceForge.
• GraphicsMagick, from ImageMagick due to concerns over the openness of development.
• The Matroska container format, from the Multimedia Container Format, due to differences in direction.
• MirOS BSD, from OpenBSD.
• Syllable Desktop, from the stagnant AtheOS.

2003

• aMule, from xMule, which itself forked from lMule shortly before, over developer disagreements.
• b2evolution, from b2/CafeLog.
• DragonFly BSD, from FreeBSD 4.8 by long-time FreeBSD developer Matt Dillon, due to disagreement over FreeBSD 5's technical direction.
• Epiphany, from Galeon, after developer disagreements about Galeon's growing complexity.
• Inkscape (vector-graphics program), from Sodipodi.
• NeoOffice is a fork of OpenOffice.org, with an incompatible license (GPL rather than LGPL), due to disagreements about licensing and about the best method to port OpenOffice.org to Mac OS X.
• The Safari renderer that became WebKit, from KHTML.
• sK1, from Skencil when the latter moved from Tk to GTK+.
• WordPress, from b2/CafeLog.
• Zen Cart, from osCommerce.

2004

• Baz, the previous version of Bazaar, from GNU arch.
• Dokeos, from Claroline.
• FrostWire, from LimeWire after LimeWire's developers considered adding RIAA-sponsored blocking code.
• MediaPortal, from XBMC.
• vTiger CRM, from SugarCRM.
• WineX (later Cedega) was a proprietary fork of Wine.
• XOrg, from XFree86, in order to adopt a more open development model and due to concerns over the latter's change to a license many distributors found unacceptable.

2005

• Audacious, from Beep Media Player to continue work on the old version of that project.
• Joomla, from Mambo due to concerns over project structure.
• RavenNuke, from PHP-Nuke after the latter was proprietised.
• Claws Mail, from Sylpheed, due to perceived slowness in accepting enhancements.

2006

• Adempiere is a community maintained fork of Compiere 2.5.3b, due to disagreement with commercial and technical direction of Compiere Inc.
• Cdrkit, from Cdrtools due to perceived licensing issues.
• LedgerSMB, from SQL-Ledger, due to disagreements over handling of security issues.
• MindTouch is a fork of MediaWiki.
• Mulgara, from Kowari after trademark threats from Northrop Grumman.

2007

• Batavi, from osCommerce, due to that project's slow release schedule.
• Go-oo, from OpenOffice.org, due to that project's contributor licensing agreement.

2008

• Boxee, a proprietary fork of XBMC.
• Dreamwidth, from LiveJournal by ex-LiveJournal developers.
• Drizzle was intended as a slimmed-down and faster fork of MySQL.
• MiaCMS, from Mambo.
• Plex, a proprietary fork of XBMC.

2009

• dbndns, from djbdns after the latter was released into the public domain and abandoned.
• Freeplane, from FreeMind.
• FusionForge, from GForge when GForge shifted focus to its proprietary version.
• Icinga, from Nagios, due to perceived slow development and problems dealing with Nagios LLC.
• kompoZer, from Nvu after that project went dormant.
• MariaDB from MySQL, over concern as to Sun Microsystems' plans for the latter.
• Pale Moon from Firefox.
• Qt Extended Improved, from Qtopia after the latter was discontinued by Qt Software.
• SciPlore MindMapping, from FreeMind.
• Voddler is a proprietary fork of XBMC and FFmpeg.

2010

• Peppermint Linux OS from Lubuntu, due to a perceived need for a cloud-centric derivative of the Ubuntu OS.
• Chamilo, from Dokeos, due to community management concerns with that project.
• LibreOffice from OpenOffice.org (and merging Go-oo), due to Oracle Corporation's perceived neglect of the software.
• OpenIndiana, from OpenSolaris after Oracle Corporation discontinued the latter.
  • Illumos, from the OpenSolaris kernel OS/Net, after Oracle closed down public access to the source code.
• webtrees, from PhpGedView, due to SourceForge's policy on exporting encryption.
• Xonotic, from Nexuiz, after that project was taken proprietary.
• Mageia, from Mandriva Linux, due to financial uncertainty and the layoff by Edge-IT, a Mandriva subsidiary employing many of the corporate staff working on the Mandriva distribution
• OpenAM, from OpenSSO after Oracle Corporation discontinued the latter.
• Calligra from KOffice after developer disagreements.

2011

• 9front from Plan 9 from Bell Labs, a community fork to accept changes not accepted for the base system.
• Fire OS, a fork of Android for the Kindle Fire
• Jenkins from Hudson (2011), due to Oracle Corporation's perceived neglect of the project's infrastructure and disagreements over use of the name on non-Oracle-maintained infrastructure.
• Univa Grid Engine, from Oracle Grid Engine, after Oracle Corporation stopped releasing project source.
• Mer started as a fork of MeeGo.

2013

• Blink, a fork of WebKit.
• SuiteCRM, from the last open source version of SugarCRM.

2014

• LibreSSL from OpenSSL.
• Nokia X software platform, a fork of the Android Open Source Project developed by Nokia exclusively for its X family of Android smartphones.

2015

• EdgeHTML from Trident

2016

• Goanna from Gecko.