到1990年時,某些因素使得共享庫(Library),應該要有比GPL更寬鬆的授權許可的需求。所以當GPL版本2在1991年6月發布,另一授權條款——程式庫通用授權條款(Library General Public License,簡稱 LGPL)也隨之誕生,並記作“版本2”以示對GPL的補充。版本號在LGPL版本2.1發布時不再相同,而LGPL也被重命名为GNU宽通用公共许可证以體現GNU的哲學觀。
根據理查德·斯托曼的說法,GPLv2的主要變化是“自由或死亡”(Liberty or Death)條款[21]。就如字面上所說,「被許可人只有在滿足所有授權條款的義務下」才可以分發包含GPL授權的軟體,儘管他們可能擁有任何其他法律義務。換句話說,就算有相互矛盾的義務,授權條款的義務也可能不被切斷。該條款旨在阻止任何一方使用專利侵權(英语:Patent infringement)索賠或其他訴訟來損害用戶在授權條款下的自由。這章中的意思是,為了在一定程度上保障和尊重其它一些人的自由和權益,無論任何人要發布源於GPL的軟體的時候,同時也須遵守強制的條款分享原始碼,否則他將根本無權發布該軟體。[註 1]
到1990年,越來越明顯的是,對於C函式庫來說,本質上已經跟受專利保護的軟件函式庫的功能表現相當,有一個限制較少授權條款對於自由軟體發展的策略上來說更為實用;因此,當GPL的版本2(GPLv2)在1991年6月發佈時,第二類別的授權條款:函式庫通用公共授權條款(英語:Library General Public License),也同時被引入,並從第二版編號開始,表明兩者是互補的。版本號在1999年發行,當時LGPL的版本2.1被發布,更名為GNU宽松通用公共授權條款(英語:Lesser General Public License),以反映其在哲學中的地位。
最常見的是“GPLv2並延伸到未來版本”的聲明,讓授權條款的用戶了解,得以允許升級到GPLv3。
GPLv3
到2005年,GPL版本3開始由斯托曼起草,由伊本·莫格林和軟件自由法律中心(Software Freedom Law Center)提供法律咨詢[27]。2005年底,自由軟件基金會 (FSF)宣布了GPL(GPLv3)第3版的工作。2006年1月16日,公佈了GPLv3的第一個“討論稿”,公眾諮詢開始。公眾諮詢原計劃為九至十五個月,但最終延長至十八個月,其中出版四份草案。2007年6月29日,官方正式版GPLv3於由FSF發布。[28]
還有一些其他的更改涉及國際化,如何處理授權條款違規,以及版權所有者如何授予額外權限。[27][29]它還增加了一項規定,“剝離”(strips)其法定價值的數位版權管理(Digital Rights Management,縮寫DRM),所以人們可以合理的當在法院被視為侵犯DRM時,去破解運行GPL軟件的任何東西,而不會違反DMCA等法律。[30]
一個關於GPL重要的爭議是,非GPL軟件是否可以動態連結到GPL庫。 GPL對GPL作品的演繹作品在GPL下發布規定很明確。但是對於動態連結到GPL庫的作品是否是演繹作品就規定得不清楚了。自由和開放原始碼社群為此分成兩派,自由軟件基金會認為這種作品就是演繹作品,但其他專家並不同意。這個問題根本的並不關乎GPL本身,而是一個版權法如何定義演繹作品。美國聯邦上訴法院第九巡迴審判庭在Galoob v. Nintendo案對演繹作品嘗試定義,但最終沒有明確的結果。
2001年微軟的首席執行官史蒂夫·巴爾默稱Linux為“癌症”,因為GPL的影響。微軟批評者指出,微軟憎惡GPL的真正原因是因為GPL對微軟的“包圍、擴展、消滅”策略起了反作用。注意微軟已以GPL為授權條款發行了SFU(Microsoft Windows Services for UNIX)中所包含的部分組件,例如GCC。
^example: if onlyGNU Lesser General Public License- (LGPL-) libraries, LGPL-software-components and components with permissive free software licenses are used (thus not GPL itself), then only the source code of LGPL parts has to be made available—for the developer's own self-developed software components this is not required (even when the underlying operating system used is licensed under GPL, as is the case with Linux).
^一个反例是 GPL'ed GNU Bison: the parsers it outputs do contain parts of itself and are therefore derivatives, which would fall under the GPL if not for a special exception granted by GNU Bison: Conditions for Using Bison. [2008-12-11]. (原始内容存档于2020-08-22).</ref>
^ 6.06.1Top 20 licenses. Black Duck Software. 2015-11-19 [2015-11-19]. (原始内容存档于2016-07-19). 1. MIT license 24%, 2. GNU General Public License (GPL) 2.0 23%, 3. Apache License 16%, 4. GNU General Public License (GPL) 3.0 9%, 5. BSD License 2.0 (3-clause, New or Revised) License 6%, 6. GNU Lesser General Public License (LGPL) 2.1 5%, 7. Artistic License (Perl) 4%, 8. GNU Lesser General Public License (LGPL) 3.0 2%, 9. Microsoft Public License 2%, 10. Eclipse Public License (EPL) 2%
^存档副本. [2017-05-03]. (原始内容存档于2020-10-08). License proliferation: a naive quantitative analysis] on lwn.net"Walter van Holst is a legal consultant at the Dutch IT consulting company mitopics.... Walter instead chose to use data from a software index, namely Freecode... Walter's 2009 data set consisted of 38,674 projects... The final column in the table shows the number of projects licensed under "any version of the GPL". In addition, Walter presented pie charts that showed the proportion of projects under various common licenses. Notable in those data sets was that, whereas in 2009 the proportion of projects licensed GPLv2-only and GPLv3 was respectively 3% and 2%, by 2013, those numbers had risen to 7% and 5%."
^Top 20 licenses. Black Duck Software. 2013-08-23 [2013-08-23]. (原始内容存档于2016-07-19). 1. GNU General Public License (GPL) 2.0 33%, 2. Apache License 13%, 3. GNU General Public License (GPL) 3.0 12%
^Why the GPL rocketed Linux to success. [2017-05-03]. (原始内容存档于2013-06-25). So while the BSDs have lost energy every time a company gets involved, the GPL'ed programs gain every time a company gets involved.
^ 15.015.1Torvalds, Linus. COPYING. kernel.org. [2013-08-13]. (原始内容存档于2015-12-17). Also note that the only valid version of the GPL as far as the kernel is concerned is _this_ particular version of the license (ie v2, not v2.2 or v3.x or whatever), unless explicitly otherwise stated.
^Linus Torvalds. Linux-2.4.0-test8. lkml.iu.edu. 2000-09-08 [2015-11-21]. (原始内容存档于2020-05-15). The only one of any note that I'd like to point out directly is the clarification in the COPYING file, making it clear that it's only _that_particular version of the GPL that is valid for the kernel. This should not come as any surprise, as that's the same license that has been there since 0.12 or so, but I thought I'd make that explicit
^Ball, Patrick. Holbrook, J. , 编. Free Software. Ethics, Science, Technology, and Engineering: A Global Resource (Farmington Hills, MI: Macmillan Reference USA). 2015, 2 (2): 291–295 [2016-11-26]. (原始内容存档于2019-10-16). Thus free software may be used and shared by anyone who accepts the terms of the license. The most common free software license is the general public license (GPL). A GPL offers the following:
^ 44.044.1James E.J. Bottomley; Mauro Carvalho Chehab; Thomas Gleixner; Christoph Hellwig; Dave Jones; Greg Kroah-Hartman; Tony Luck; Andrew Morton; Trond Myklebust; David Woodhouse. Kernel developers' position on GPLv3 - The Dangers and Problems with GPLv3. LWN.net. 2006-09-15 [2015-03-11]. (原始内容存档于2021-01-18). The current version (Discussion Draft 2) of GPLv3 on first reading fails the necessity test of section 1 on the grounds that there's no substantial and identified problem with GPLv2 that it is trying to solve. However, a deeper reading reveals several other problems with the current FSF draft: 5.1 DRM Clauses... 5.2 Additional Restrictions Clause... 5.3 Patents Provisions... since the FSF is proposing to shift all of its projects to GPLv3 and apply pressure to every other GPL licensed project to move, we foresee the release of GPLv3 portends the Balkanisation of the entire Open Source Universe upon which we rely.
^Petreley, Nicholas. A fight against evil or a fight for attention?. linuxjournal.com. 2006-09-27 [2015-03-11]. (原始内容存档于2018-03-02). Second, the war between Linus Torvalds and other Kernel developers and the Free Software Foundation over GPLv3 is continuing, with Torvalds saying he's fed up with the FSF.
^Kerner, Sean Michael. Torvalds Still Keen On GPLv2. internetnews.com. 2008-01-08 [2015-02-12]. (原始内容存档于2015-02-12). "In some ways, Linux was the project that really made the split clear between what the FSF is pushing which is very different from what open source and Linux has always been about, which is more of a technical superiority instead of a -- this religious belief in freedom," Torvalds told Zemlin. So, the GPL Version 3 reflects the FSF's goals and the GPL Version 2 pretty closely matches what I think a license should do and so right now, Version 2 is where the kernel is."