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3  <title>The Free Software Definition - GNU Project - Free Software Foundation (FSF)</title>  <title>What is free software?
4    - GNU Project - Free Software Foundation</title>
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16    
17  <h2>The Free Software Definition</h2>  <h2>What is free software?</h2>
18    
19  <p>  <div class="article">
20  We maintain this free software definition to show clearly what must  <h3>The Free Software Definition</h3>
21  be true about a particular software program for it to be considered  
22  free software.  <blockquote class="note" id="fsf-licensing"><p style="font-size: 80%">
23    Have a question about free software licensing not answered here?
24    See our other <a href="http://www.fsf.org/licensing">licensing resources</a>,
25    and if necessary contact the FSF Compliance Lab
26    at <a href="mailto:licensing@fsf.org">licensing@fsf.org</a>.</p>
27    </blockquote>
28    
29    <div class="comment">
30    <p>
31    The free software definition presents the criteria for whether a
32    particular software program qualifies as free software.  From time to
33    time we revise this definition, to clarify it or to resolve questions
34    about subtle issues.  See the <a href="#History">History section</a>
35    below for a list of changes that affect the definition of free
36    software.
37  </p>  </p>
38    
39  <p>  <p>
40  <q>Free software</q> is a matter of liberty, not price.  To understand  &ldquo;Open source&rdquo; is something different: it has a very
41  the concept, you should think of <q>free</q> as in <q>free speech,</q>  different philosophy based on different values.  Its practical
42  not as in <q>free beer.</q>  definition is different too, but nearly all open source programs are
43    in fact free.  We explain the
44    difference in <a href="/philosophy/open-source-misses-the-point.html">
45    Why &ldquo;Open Source&rdquo; misses the point of Free Software</a>.
46  </p>  </p>
47    </div>
48    
49  <p>  <p>
50  Free software is a matter of the users' freedom to run, copy, distribute,  &ldquo;Free software&rdquo; means software that respects users'
51  study, change and improve the software.  More precisely, it refers to  freedom and community.  Roughly, it means that <b>the users have the
52  four kinds of freedom, for the users of the software:  freedom to run, copy, distribute, study, change and improve the
53    software</b>.  Thus, &ldquo;free software&rdquo; is a matter of
54    liberty, not price.  To understand the concept, you should think of
55    &ldquo;free&rdquo; as in &ldquo;free speech,&rdquo; not as in
56    &ldquo;free beer&rdquo;.  We sometimes call it &ldquo;libre
57    software,&rdquo; borrowing the French or Spanish word for
58    &ldquo;free&rdquo; as in freedom, to show we do not mean the software
59    is gratis.
60  </p>  </p>
61    
62  <ul>  <p>
63    <li>The freedom to run the program, for any purpose (freedom 0).</li>  We campaign for these freedoms because everyone deserves them.  With
64    <li>The freedom to study how the program works, and adapt it to  these freedoms, the users (both individually and collectively) control
65        your needs (freedom 1). Access to the source code is a precondition  the program and what it does for them.  When users don't control the
66        for this.  program, we call it a &ldquo;nonfree&rdquo; or
67    &ldquo;proprietary&rdquo; program.  The nonfree program controls the
68    users, and the developer controls the program; this makes the
69    program <a href="/philosophy/free-software-even-more-important.html">
70    an instrument of unjust power</a>.
71    </p>
72    
73    <h4> The four essential freedoms</h4>
74    
75    <p>
76    A program is free software if the program's users have the
77    four essential freedoms: <a href="#f1">[1]</a>
78    </p>
79    
80    <ul class="important">
81      <li>The freedom to run the program as you wish,
82          for any purpose (freedom 0).</li>
83      <li>The freedom to study how the program works, and change it so it
84          does your computing as you wish (freedom 1). Access to the source
85          code is a precondition for this.
86    </li>    </li>
87    <li>The freedom to redistribute copies so you can help your neighbor    <li>The freedom to redistribute copies so you can help others
88        (freedom 2).        (freedom 2).
89    </li>    </li>
90    <li>The freedom to improve the program, and release your improvements    <li>The freedom to distribute copies of your modified versions
91        to the public, so that the whole community benefits (freedom 3).        to others (freedom 3).  By doing this you can give the whole
92          community a chance to benefit from your changes.
93        Access to the source code is a precondition for this.        Access to the source code is a precondition for this.
94    </li>    </li>
95  </ul>  </ul>
96    
97  <p>  <p>
98  A program is free software if users have all of these freedoms.  Thus,  A program is free software if it gives users adequately all of these
99  you should be free to redistribute copies, either with or without  freedoms.  Otherwise, it is nonfree.  While we can distinguish various
100  modifications, either gratis or charging a fee for distribution, to  nonfree distribution schemes in terms of how far they fall short of
101  <a href="#exportcontrol">anyone anywhere</a>.  Being free to do these  being free, we consider them all equally unethical.</p>
102  things means (among other things) that you do not have to ask or pay  
103  for permission.  <p>In any given scenario, these freedoms must apply to whatever code
104  </p>  we plan to make use of, or lead others to make use of.  For instance,
105    consider a program A which automatically launches a program B to
106    handle some cases.  If we plan to distribute A as it stands, that
107    implies users will need B, so we need to judge whether both A and B
108    are free.  However, if we plan to modify A so that it doesn't use B,
109    only A needs to be free; B is not pertinent to that plan.</p>
110    
111  <p>  <p>
112  You should also have the freedom to make modifications and use them  &ldquo;Free software&rdquo; does not mean &ldquo;noncommercial&rdquo;.  A free
113  privately in your own work or play, without even mentioning that they  program must be available for commercial use, commercial development,
114  exist.  If you do publish your changes, you should not be required to  and commercial distribution.  Commercial development of free software
115  notify anyone in particular, or in any particular way.  is no longer unusual; such free commercial software is very important.
116    You may have paid money to get copies of free software, or you may have
117    obtained copies at no charge.  But regardless of how you got your copies,
118    you always have the freedom to copy and change the software, even to
119    <a href="/philosophy/selling.html">sell copies</a>.
120  </p>  </p>
121    
122    <p>The rest of this page clarifies certain points about what makes
123    specific freedoms adequate or not.</p>
124    
125    <h4>The freedom to run the program as you wish</h4>
126    
127  <p>  <p>
128  The freedom to run the program means the freedom for any kind of person  The freedom to run the program means the freedom for any kind of person
129  or organization to use it on any kind of computer system, for any kind of  or organization to use it on any kind of computer system, for any kind of
130  overall job and purpose, without being required to communicate about it  overall job and purpose, without being required to communicate about it
131  with the developer or any other specific entity.  In this freedom, it is  with the developer or any other specific entity.  In this freedom, it is
132  the <em>user's</em> purpose that matters, not the <em>developer's</em>  the <em>user's</em> purpose that matters, not the <em>developer's</em>
133  purpose; you as a user are free to run a program for your purposes,  purpose; you as a user are free to run the program for your purposes,
134  and if you distribute it to someone else, she is then free to run it  and if you distribute it to someone else, she is then free to run it
135  for her purposes, but you are not entitled to impose your purposes on her.  for her purposes, but you are not entitled to impose your purposes on her.
136  </p>  </p>
137    
138  <p>  <p>
139  The freedom to redistribute copies must include binary or executable  The freedom to run the program as you wish means that you are not
140  forms of the program, as well as source code, for both modified and  forbidden or stopped from making it run.  This has nothing to do with what
141  unmodified versions.  (Distributing programs in runnable form is necessary  functionality the program has, whether it is technically capable of
142  for conveniently installable free operating systems.)  It is ok if there  functioning in any given environment, or whether it is useful for any
143  is no way to produce a binary or executable form for a certain program  particular computing activity.</p>
144  (since some languages don't support that feature), but you must have the  
145  freedom to redistribute such forms should you find or develop a way to  <h4>The freedom to study the source code and make changes</h4>
146  make them.  
147    <p>
148    In order for freedoms 1 and 3 (the freedom to make changes and the
149    freedom to publish the changed versions) to be meaningful, you must have
150    access to the source code of the program.  Therefore, accessibility of
151    source code is a necessary condition for free software.  Obfuscated
152    &ldquo;source code&rdquo; is not real source code and does not count
153    as source code.
154  </p>  </p>
155    
156  <p>  <p>
157  In order for the freedoms to make changes, and to publish improved  Freedom 1 includes the freedom to use your changed version in place of
158  versions, to be meaningful, you must have access to the source code of  the original.  If the program is delivered in a product designed to
159  the program.  Therefore, accessibility of source code is a necessary  run someone else's modified versions but refuse to run yours &mdash; a
160  condition for free software.  practice known as &ldquo;tivoization&rdquo; or &ldquo;lockdown&rdquo;,
161    or (in its practitioners' perverse terminology) as &ldquo;secure
162    boot&rdquo; &mdash; freedom 1 becomes an empty pretense rather than a
163    practical reality.  These binaries are not free
164    software even if the source code they are compiled from is free.
165  </p>  </p>
166    
167  <p>  <p>
168  One important way to modify a program is by merging in available  One important way to modify a program is by merging in available free
169  free subroutines and modules.  If the program's license says that you  subroutines and modules.  If the program's license says that you
170  cannot merge in an existing module, such as if it requires you to be the  cannot merge in a suitably licensed existing module &mdash; for instance, if it
171  copyright holder of any code you add, then the license is too restrictive  requires you to be the copyright holder of any code you add &mdash; then the
172  to qualify as free.  license is too restrictive to qualify as free.
173  </p>  </p>
174    
175  <p>  <p>
176  In order for these freedoms to be real, they must be irrevocable as  Whether a change constitutes an improvement is a subjective matter.
177  long as you do nothing wrong; if the developer of the software has the  If your right to modify a program is limited, in substance, to changes that
178  power to revoke the license, without your doing anything to give cause,  someone else considers an improvement, that program is not free.
179  the software is not free.  </p>
180    
181    <h4>The freedom to redistribute if you wish: basic requirements</h4>
182    
183    <p>Freedom to distribute (freedoms 2 and 3) means you are free to
184    redistribute copies, either with or without modifications, either
185    gratis or charging a fee for distribution, to
186    <a href="#exportcontrol">anyone anywhere</a>.  Being free to do these
187    things means (among other things) that you do not have to ask or pay
188    for permission to do so.
189  </p>  </p>
190    
191  <p>  <p>
192  However, certain kinds of rules about the manner of distributing free  You should also have the freedom to make modifications and use them
193  software are acceptable, when they don't conflict with the central  privately in your own work or play, without even mentioning that they
194  freedoms.  For example, copyleft (very simply stated) is the rule that  exist.  If you do publish your changes, you should not be required to
195  when redistributing the program, you cannot add restrictions to deny  notify anyone in particular, or in any particular way.
 other people the central freedoms.  This rule does not conflict with  
 the central freedoms; rather it protects them.  
196  </p>  </p>
197    
198  <p>  <p>
199  You may have paid money to get copies of free software, or you may have  Freedom 3 includes the freedom to release your modified versions
200  obtained copies at no charge.  But regardless of how you got your copies,  as free software.  A free license may also permit other ways of
201  you always have the freedom to copy and change the software, even to  releasing them; in other words, it does not have to be
202  <a href="/philosophy/selling.html">sell copies</a>.  a <a href="/copyleft/copyleft.html">copyleft</a> license.  However, a
203    license that requires modified versions to be nonfree does not qualify
204    as a free license.
205  </p>  </p>
206    
207  <p>  <p>
208  <q>Free software</q> does not mean <q>non-commercial.</q>  A free  The freedom to redistribute copies must include binary or executable
209  program must be available for commercial use, commercial development,  forms of the program, as well as source code, for both modified and
210  and commercial distribution.  Commercial development of free software  unmodified versions.  (Distributing programs in runnable form is necessary
211  is no longer unusual; such free commercial software is very important.  for conveniently installable free operating systems.)  It is OK if there
212    is no way to produce a binary or executable form for a certain program
213    (since some languages don't support that feature), but you must have the
214    freedom to redistribute such forms should you find or develop a way to
215    make them.
216  </p>  </p>
217    
218    <h4>Copyleft</h4>
219    
220  <p>  <p>
221  Rules about how to package a modified version are acceptable, if they  Certain kinds of rules about the manner of distributing free
222  don't substantively block your freedom to release modified versions, or  software are acceptable, when they don't conflict with the central
223  your freedom to make and use modified versions privately.  Rules that <q>if  freedoms.  For example, <a href="/copyleft/copyleft.html">copyleft</a>
224  you make your version available in this way, you must make it available in  (very simply stated) is the rule that when redistributing the program,
225  that way also</q> can be acceptable too, on the same condition.  (Note that  you cannot add restrictions to deny other people the central freedoms.
226  such a rule still leaves you the choice of whether to publish your version  This rule does not conflict with the central freedoms; rather it
227  at all.)  Rules that require release of source code to the users for  protects them.
228  versions that you put into public use are also acceptable.  It is also  </p>
229  acceptable for the license to require that, if you have distributed a  
230  modified version and a previous developer asks for a copy of it, you  <p>
231  must send one, or that you identify yourself on your modifications.  In the GNU project, we use copyleft to protect the four freedoms
232    legally for everyone.  We believe there are important reasons why
233    <a href="/philosophy/pragmatic.html">it is better to use
234    copyleft</a>.  However,
235    <a href="/philosophy/categories.html#Non-CopyleftedFreeSoftware">
236    noncopylefted free software</a> is ethical
237    too.  See <a href="/philosophy/categories.html">Categories of Free
238    Software</a> for a description of how &ldquo;free software,&rdquo;
239    &ldquo;copylefted software&rdquo; and other categories of software
240    relate to each other.
241  </p>  </p>
242    
243    <h4>Rules about packaging and distribution details</h4>
244    
245  <p>  <p>
246  In the GNU project, we use  Rules about how to package a modified version are acceptable,
247  <q><a href="/copyleft/copyleft.html">copyleft</a></q>  if they don't substantively limit your freedom to release modified
248  to protect these freedoms legally for everyone.  But  versions, or your freedom to make and use modified versions privately.
249  <a href="/philosophy/categories.html#Non-CopyleftedFreeSoftware">non-copylefted  Thus, it is acceptable for the license to require that you change the
250  free software</a> also exists.  We believe there are important reasons why  name of the modified version, remove a logo, or identify your
251  <a href="/philosophy/pragmatic.html"> it is better to use copyleft</a>,  modifications as yours.  As long as these requirements are not so
252  but if your program is non-copylefted free software, we can still  burdensome that they effectively hamper you from releasing your
253  use it.  changes, they are acceptable; you're already making other changes to
254    the program, so you won't have trouble making a few more.
255  </p>  </p>
256    
257  <p>  <p>
258  See <a href="/philosophy/categories.html">Categories of Free Software</a>  Rules that &ldquo;if you make your version available in this way, you
259  for a description of how <q>free software,</q> <q>copylefted software</q>  must make it available in that way also&rdquo; can be acceptable too,
260  and other categories of software relate to each other.  on the same condition.  An example of such an acceptable rule is one
261    saying that if you have distributed a
262    modified version and a previous developer asks for a copy of it, you
263    must send one.  (Note that such a rule still leaves you the choice of
264    whether to distribute your version at all.)  Rules that require release
265    of source code to the users for versions that you put into public use
266    are also acceptable.
267  </p>  </p>
268    
269  <p>  <p>
270    A special issue arises when a license requires changing the name by
271    which the program will be invoked from other programs.  That
272    effectively hampers you from releasing your changed version so that it
273    can replace the original when invoked by those other programs.  This
274    sort of requirement is acceptable only if there's a suitable aliasing
275    facility that allows you to specify the original program's name as an
276    alias for the modified version.</p>
277    
278    <h4>Export regulations</h4>
279    
280    <p>
281  Sometimes government <a id="exportcontrol">export control regulations</a>  Sometimes government <a id="exportcontrol">export control regulations</a>
282  and trade sanctions can constrain your freedom to distribute copies of  and trade sanctions can constrain your freedom to distribute copies of
283  programs internationally.  Software developers do not have the power to  programs internationally.  Software developers do not have the power to
284  eliminate or override these restrictions, but what they can and must do  eliminate or override these restrictions, but what they can and must do
285  is refuse to impose them as conditions of use of the program.  In this  is refuse to impose them as conditions of use of the program.  In this
286  way, the restrictions will not affect activities and people outside the  way, the restrictions will not affect activities and people outside the
287  jurisdictions of these governments.  jurisdictions of these governments.  Thus, free software licenses
288    must not require obedience to any nontrivial export regulations as a
289    condition of exercising any of the essential freedoms.
290  </p>  </p>
291    
292  <p>  <p>
293    Merely mentioning the existence of export regulations, without making
294    them a condition of the license itself, is acceptable since it does
295    not restrict users.  If an export regulation is actually trivial for
296    free software, then requiring it as a condition is not an actual
297    problem; however, it is a potential problem, since a later change in
298    export law could make the requirement nontrivial and thus render the
299    software nonfree.
300    </p>
301    
302    <h4>Legal considerations</h4>
303    
304    <p>
305    In order for these freedoms to be real, they must be permanent and
306    irrevocable as long as you do nothing wrong; if the developer of the
307    software has the power to revoke the license, or retroactively add
308    restrictions to its terms, without your doing anything wrong to give
309    cause, the software is not free.
310    </p>
311    
312    <p>
313    A free license may not require compliance with the license of a
314    nonfree program.  Thus, for instance, if a license requires you to
315    comply with the licenses of &ldquo;all the programs you use&rdquo;, in
316    the case of a user that runs nonfree programs this would require
317    compliance with the licenses of those nonfree programs; that makes the
318    license nonfree.
319    </p>
320    
321    <p>
322    It is acceptable for a free license to specify which jurisdiction's
323    law applies, or where litigation must be done, or both.
324    </p>
325    
326    <h4>Contract-based licenses</h4>
327    
328    <p>
329  Most free software licenses are based on copyright, and there are limits  Most free software licenses are based on copyright, and there are limits
330  on what kinds of requirements can be imposed through copyright.  If a  on what kinds of requirements can be imposed through copyright.  If a
331  copyright-based license respects freedom in the ways described above, it  copyright-based license respects freedom in the ways described above, it
# Line 176  is unlikely to have some other sort of p Line 333  is unlikely to have some other sort of p
333  (though this does happen occasionally).  However, some free software  (though this does happen occasionally).  However, some free software
334  licenses are based on contracts, and contracts can impose a much larger  licenses are based on contracts, and contracts can impose a much larger
335  range of possible restrictions.  That means there are many possible ways  range of possible restrictions.  That means there are many possible ways
336  such a license could be unacceptably restrictive and non-free.  such a license could be unacceptably restrictive and nonfree.
337  </p>  </p>
338    
339  <p>  <p>
# Line 184  We can't possibly list all the ways that Line 341  We can't possibly list all the ways that
341  contract-based license restricts the user in an unusual way that  contract-based license restricts the user in an unusual way that
342  copyright-based licenses cannot, and which isn't mentioned here as  copyright-based licenses cannot, and which isn't mentioned here as
343  legitimate, we will have to think about it, and we will probably conclude  legitimate, we will have to think about it, and we will probably conclude
344  it is non-free.  it is nonfree.
345  </p>  </p>
346    
347    <h4>Use the right words when talking about free software</h4>
348    
349  <p>  <p>
350  When talking about free software, it is best to avoid using terms  When talking about free software, it is best to avoid using terms
351  like <q>give away</q> or <q>for free,</q> because those terms imply that  like &ldquo;give away&rdquo; or &ldquo;for free,&rdquo; because those terms imply that
352  the issue is about price, not freedom.  Some common terms such  the issue is about price, not freedom.  Some common terms such
353  as <q>piracy</q> embody opinions we hope you won't endorse.  See  as &ldquo;piracy&rdquo; embody opinions we hope you won't endorse.  See
354  <a href="/philosophy/words-to-avoid.html">Confusing Words and Phrases that  <a href="/philosophy/words-to-avoid.html">Confusing Words and Phrases that
355  are Worth Avoiding</a> for a discussion of these terms.  We also have  are Worth Avoiding</a> for a discussion of these terms.  We also have
356  a list of <a href="/philosophy/fs-translations.html">translations of  a list of proper <a href="/philosophy/fs-translations.html">translations of
357  <q>free software</q></a> into various languages.  &ldquo;free software&rdquo;</a> into various languages.
358  </p>  </p>
359    
360    <h4>How we interpret these criteria</h4>
361    
362  <p>  <p>
363  Finally, note that criteria such as those stated in this free software  Finally, note that criteria such as those stated in this free software
364  definition require careful thought for their interpretation.  To decide  definition require careful thought for their interpretation.  To decide
# Line 212  a conclusion about a new issue, we often Line 373  a conclusion about a new issue, we often
373  it easier to see why certain licenses do or don't qualify.  it easier to see why certain licenses do or don't qualify.
374  </p>  </p>
375    
376    <h4>Get help with free licenses</h4>
377    
378  <p>  <p>
379  If you are interested in whether a specific license qualifies as a free  If you are interested in whether a specific license qualifies as a free
380  software license, see our <a href="/licenses/license-list.html">list  software license, see our <a href="/licenses/license-list.html">list
# Line 221  listed there, you can ask us about it by Line 384  listed there, you can ask us about it by
384  </p>  </p>
385    
386  <p>  <p>
387  If you are contemplating writing a new license, please contact the FSF  If you are contemplating writing a new license, please contact the
388  by writing to that address. The proliferation of different free software  Free Software Foundation first by writing to that address. The
389  licenses means increased work for users in understanding the licenses;  proliferation of different free software licenses means increased work
390  we may be able to help you find an existing Free Software license that  for users in understanding the licenses; we may be able to help you
391  meets your needs.  find an existing free software license that meets your needs.
392  </p>  </p>
393    
394  <p>  <p>
395  If that isn't possible, if you really need a new license, with our  If that isn't possible, if you really need a new license, with our
396  help you can ensure that the license really is a Free Software license  help you can ensure that the license really is a free software license
397  and avoid various practical problems.  and avoid various practical problems.
398  </p>  </p>
399    
400  <h2 id="beyond-software">Beyond Software</h2>  <h3 id="beyond-software">Beyond Software</h3>
401    
402  <p>  <p>
403  <a href="/philosophy/free-doc.html">Software manuals must be free</a>,  <a href="/philosophy/free-doc.html">Software manuals must be free</a>,
# Line 246  manuals are in effect part of the softwa Line 409  manuals are in effect part of the softwa
409  The same arguments also make sense for other kinds of works of  The same arguments also make sense for other kinds of works of
410  practical use &mdash; that is to say, works that embody useful knowledge,  practical use &mdash; that is to say, works that embody useful knowledge,
411  such as educational works and reference  such as educational works and reference
412  works.  <a href="http://wikipedia.org">Wikipedia</a> is the best known  works.  <a href="http://wikipedia.org">Wikipedia</a> is the best-known
413  example.  example.
414  </p>  </p>
415    
# Line 256  has been extended to a definition of <a Line 419  has been extended to a definition of <a
419  free cultural works</a> applicable to any kind of works.  free cultural works</a> applicable to any kind of works.
420  </p>  </p>
421    
422  <h2 id="open-source">Open Source?</h2>  <h3 id="open-source">Open Source?</h3>
423    
424  <p>  <p>
425  Another group has started using the term <q>open source</q> to mean  Another group uses the term &ldquo;open source&rdquo; to mean
426  something close (but not identical) to <q>free software.</q>  We  something close (but not identical) to &ldquo;free software&rdquo;.  We
427  prefer the term <q>free software</q> because, once you have heard that  prefer the term &ldquo;free software&rdquo; because, once you have heard that
428  it refers to freedom rather than price, it calls to mind freedom.  The  it refers to freedom rather than price, it calls to mind freedom.  The
429  word <q>open</q> <a href="/philosophy/open-source-misses-the-point.html">  word &ldquo;open&rdquo; <a href="/philosophy/open-source-misses-the-point.html">
430  never refers to freedom</a>.  never refers to freedom</a>.
431  </p>  </p>
   
432  </div>  </div>
433    
434    <h3 id="History">History</h3>
435    
436  <!--#include virtual="/server/footer.html" -->  <p>From time to time we revise this Free Software Definition.  Here is
437    the list of substantive changes, along with links to show exactly what
438    was changed.</p>
439    
440    <ul>
441    
442    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.152&amp;r2=1.153">Version
443    1.153</a>: Clarify that freedom to run the program means nothing stops
444    you from making it run.</li>
445    
446    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.140&amp;r2=1.141">Version
447    1.141</a>: Clarify which code needs to be free.</li>
448    
449    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.134&amp;r2=1.135">Version
450    1.135</a>: Say each time that freedom 0 is the freedom to run the program
451    as you wish.</li>
452    
453    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.133&amp;r2=1.134">Version
454    1.134</a>: Freedom 0 is not a matter of the program's functionality.</li>
455    
456    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.130&amp;r2=1.131">Version
457    1.131</a>: A free license may not require compliance with a nonfree license
458    of another program.</li>
459    
460    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.128&amp;r2=1.129">Version
461    1.129</a>: State explicitly that choice of law and choice of forum
462    specifications are allowed.  (This was always our policy.)</li>
463    
464    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.121&amp;r2=1.122">Version
465    1.122</a>: An export control requirement is a real problem if the
466    requirement is nontrivial; otherwise it is only a potential problem.</li>
467    
468    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.117&amp;r2=1.118">Version
469    1.118</a>: Clarification: the issue is limits on your right to modify,
470    not on what modifications you have made.  And modifications are not limited
471    to &ldquo;improvements&rdquo;</li>
472    
473    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.110&amp;r2=1.111">Version
474    1.111</a>: Clarify 1.77 by saying that only
475    retroactive <em>restrictions</em> are unacceptable.  The copyright
476    holders can always grant additional <em>permission</em> for use of the
477    work by releasing the work in another way in parallel.</li>
478    
479    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.104&amp;r2=1.105">Version
480    1.105</a>: Reflect, in the brief statement of freedom 1, the point
481    (already stated in version 1.80) that it includes really using your modified
482    version for your computing.</li>
483    
484    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.91&amp;r2=1.92">Version
485    1.92</a>: Clarify that obfuscated code does not qualify as source code.</li>
486    
487    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.89&amp;r2=1.90">Version
488    1.90</a>: Clarify that freedom 3 means the right to distribute copies
489    of your own modified or improved version, not a right to participate
490    in someone else's development project.</li>
491    
492    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.88&amp;r2=1.89">Version
493    1.89</a>: Freedom 3 includes the right to release modified versions as
494    free software.</li>
495    
496    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.79&amp;r2=1.80">Version
497    1.80</a>: Freedom 1 must be practical, not just theoretical;
498    i.e., no tivoization.</li>
499    
500    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.76&amp;r2=1.77">Version
501    1.77</a>: Clarify that all retroactive changes to the license are
502    unacceptable, even if it's not described as a complete
503    replacement.</li>
504    
505    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.73&amp;r2=1.74">Version
506    1.74</a>: Four clarifications of points not explicit enough, or stated
507    in some places but not reflected everywhere:
508    <ul>
509    <li>"Improvements" does not mean the license can
510    substantively limit what kinds of modified versions you can release.
511    Freedom 3 includes distributing modified versions, not just changes.</li>
512    <li>The right to merge in existing modules
513    refers to those that are suitably licensed.</li>
514    <li>Explicitly state the conclusion of the point about export controls.</li>
515    <li>Imposing a license change constitutes revoking the old license.</li>
516    </ul>
517    </li>
518    
519    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.56&amp;r2=1.57">Version
520    1.57</a>: Add &quot;Beyond Software&quot; section.</li>
521    
522    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.45&amp;r2=1.46">Version
523    1.46</a>: Clarify whose purpose is significant in the freedom to run
524    the program for any purpose.</li>
525    
526    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.40&amp;r2=1.41">Version
527    1.41</a>: Clarify wording about contract-based licenses.</li>
528    
529    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.39&amp;r2=1.40">Version
530    1.40</a>: Explain that a free license must allow to you use other
531    available free software to create your modifications.</li>
532    
533    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.38&amp;r2=1.39">Version
534    1.39</a>: Note that it is acceptable for a license to require you to
535    provide source for versions of the software you put into public
536    use.</li>
537    
538    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.30&amp;r2=1.31">Version
539    1.31</a>: Note that it is acceptable for a license to require you to
540    identify yourself as the author of modifications.  Other minor
541    clarifications throughout the text.</li>
542    
543    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.22&amp;r2=1.23">Version
544    1.23</a>: Address potential problems related to contract-based
545    licenses.</li>
546    
547    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.15&amp;r2=1.16">Version
548    1.16</a>: Explain why distribution of binaries is important.</li>
549    
550    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.10&amp;r2=1.11">Version
551    1.11</a>: Note that a free license may require you to send a copy of
552    versions you distribute to previous developers on request.</li>
553    
554    </ul>
555    
556    <p>There are gaps in the version numbers shown above because there are
557    other changes in this page that do not affect the definition or its
558    interpretations.  For instance, the list does not include changes in
559    asides, formatting, spelling, punctuation, or other parts of the page.
560    You can review the complete list of changes to the page through
561    the <a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;view=log">cvsweb
562    interface</a>.</p>
563    
564    <h3 style="font-size:1em">Footnote</h3>
565    <ol>
566    <li id="f1">The reason they are numbered 0, 1, 2 and 3 is historical. Around
567    1990 there were three freedoms, numbered 1, 2 and 3. Then we realized that
568    the freedom to run the program needed to be mentioned explicitly.
569    It was clearly more basic than the other three, so it properly should
570    precede them. Rather than renumber the others, we made it freedom&nbsp;0.</li>
571    </ol>
572    
573    </div><!-- for id="content", starts in the include above -->
574    <!--#include virtual="/server/footer.html" -->
575  <div id="footer">  <div id="footer">
576    <div class="unprintable">
577    
578  <p>  <p>Please send general FSF &amp; GNU inquiries to
579  Please send FSF &amp; GNU inquiries to  <a href="mailto:gnu@gnu.org">&lt;gnu@gnu.org&gt;</a>.
580  <a href="mailto:gnu@gnu.org"><em>gnu@gnu.org</em></a>.  There are also <a href="/contact/">other ways to contact</a>
581  There are also <a href="/contact/">other ways to contact</a>  the FSF.  Broken links and other corrections or suggestions can be sent
582  the FSF.  to <a href="mailto:webmasters@gnu.org">&lt;webmasters@gnu.org&gt;</a>.</p>
583  <br />  
584  Please send broken links and other corrections or suggestions to  <p><!-- TRANSLATORS: Ignore the original text in this paragraph,
585  <a href="mailto:webmasters@gnu.org"><em>webmasters@gnu.org</em></a>.          replace it with the translation of these two:
586  </p>  
587            We work hard and do our best to provide accurate, good quality
588            translations.  However, we are not exempt from imperfection.
589            Please send your comments and general suggestions in this regard
590            to <a href="mailto:web-translators@gnu.org">
591            &lt;web-translators@gnu.org&gt;</a>.</p>
592    
593            <p>For information on coordinating and submitting translations of
594            our web pages, see <a
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597    Please see the <a
598    href="/server/standards/README.translations.html">Translations
599    README</a> for information on coordinating and submitting translations
600    of this article.</p>
601    </div>
602    
603  <p>  <!-- Regarding copyright, in general, standalone pages (as opposed to
604  Please see the       files generated as part of manuals) on the GNU web server should
605  <a href="/server/standards/README.translations.html">Translations       be under CC BY-ND 4.0.  Please do NOT change or remove this
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611         If you wish to list earlier years, that is ok too.
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615         being publicly visible on the web or in a revision control system).
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619    
620    <p>Copyright &copy; 1996, 2002, 2004-2007, 2009-2018
621    Free Software Foundation, Inc.</p>
622    
623    <p>This page is licensed under a <a rel="license"
624    href="http://creativecommons.org/licenses/by-nd/4.0/">Creative
625    Commons Attribution-NoDerivatives 4.0 International License</a>.</p>
626    
627  <p>  <!--#include virtual="/server/bottom-notes.html" -->
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 </p>  
628    
629  <p>  <p class="unprintable">Updated:
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630  <!-- timestamp start -->  <!-- timestamp start -->
631  $Date$  $Date$
632  <!-- timestamp end -->  <!-- timestamp end -->
633  </p>  </p>
634  </div>  </div>
635    </div><!-- for class="inner", starts in the banner include -->
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