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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    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>
112    &ldquo;Free software&rdquo; does not mean &ldquo;noncommercial&rdquo;.  A free
113    program must be available for commercial use, commercial development,
114    and commercial distribution.  Commercial development of free software
115    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>  <p>
123  You should also have the freedom to make modifications and use them  A free program must offer the four freedoms to any user that obtains a
124  privately in your own work or play, without even mentioning that they  copy of the software, provided the user has complied thus far with the
125  exist.  If you do publish your changes, you should not be required to  conditions of the free license covering the software.  Putting some of
126  notify anyone in particular, or in any particular way.  the freedoms off limits to some users, or requiring that users pay, in
127    money or in kind, to exercise them, is tantamount to not granting the
128    freedoms in question, and thus renders the program nonfree.
129  </p>  </p>
130    
131    <h3>Clarifying the line at various points</h3>
132    
133    <p>In the rest of this article we expain more precisely how far the
134    various freedoms need to extend, on various issues, in order for a
135    program to be free.</p>
136    
137    <h4>The freedom to run the program as you wish</h4>
138    
139  <p>  <p>
140  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
141  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
142  overall job and purpose, without being required to communicate about it  overall job and purpose, without being required to communicate about it
143  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
144  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>
145  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,
146  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
147  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.
148  </p>  </p>
149    
150  <p>  <p>
151  The freedom to redistribute copies must include binary or executable  The freedom to run the program as you wish means that you are not
152  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
153  unmodified versions.  (Distributing programs in runnable form is necessary  functionality the program has, whether it is technically capable of
154  for conveniently installable free operating systems.)  It is ok if there  functioning in any given environment, or whether it is useful for any
155  is no way to produce a binary or executable form for a certain program  particular computing activity.</p>
156  (since some languages don't support that feature), but you must have the  
157  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>
158  make them.  
159    <p>
160    In order for freedoms 1 and 3 (the freedom to make changes and the
161    freedom to publish the changed versions) to be meaningful, you need to have
162    access to the source code of the program.  Therefore, accessibility of
163    source code is a necessary condition for free software.  Obfuscated
164    &ldquo;source code&rdquo; is not real source code and does not count
165    as source code.
166  </p>  </p>
167    
168  <p>  <p>
169  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
170  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
171  the program.  Therefore, accessibility of source code is a necessary  run someone else's modified versions but refuse to run yours &mdash; a
172  condition for free software.  practice known as &ldquo;tivoization&rdquo; or &ldquo;lockdown&rdquo;,
173    or (in its practitioners' perverse terminology) as &ldquo;secure
174    boot&rdquo; &mdash; freedom 1 becomes an empty pretense rather than a
175    practical reality.  These binaries are not free
176    software even if the source code they are compiled from is free.
177  </p>  </p>
178    
179  <p>  <p>
180  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
181  free subroutines and modules.  If the program's license says that you  subroutines and modules.  If the program's license says that you
182  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
183  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
184  to qualify as free.  license is too restrictive to qualify as free.
185  </p>  </p>
186    
187  <p>  <p>
188  In order for these freedoms to be real, they must be irrevocable as  Whether a change constitutes an improvement is a subjective matter.
189  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
190  power to revoke the license, without your doing anything to give cause,  someone else considers an improvement, that program is not free.
191  the software is not free.  </p>
192    
193    <h4>The freedom to redistribute if you wish: basic requirements</h4>
194    
195    <p>Freedom to distribute (freedoms 2 and 3) means you are free to
196    redistribute copies, either with or without modifications, either
197    gratis or charging a fee for distribution, to
198    <a href="#exportcontrol">anyone anywhere</a>.  Being free to do these
199    things means (among other things) that you do not have to ask or pay
200    for permission to do so.
201  </p>  </p>
202    
203  <p>  <p>
204  However, certain kinds of rules about the manner of distributing free  You should also have the freedom to make modifications and use them
205  software are acceptable, when they don't conflict with the central  privately in your own work or play, without even mentioning that they
206  freedoms.  For example, copyleft (very simply stated) is the rule that  exist.  If you do publish your changes, you should not be required to
207  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.  
208  </p>  </p>
209    
210  <p>  <p>
211  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
212  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
213  you always have the freedom to copy and change the software, even to  releasing them; in other words, it does not have to be
214  <a href="/philosophy/selling.html">sell copies</a>.  a <a href="/copyleft/copyleft.html">copyleft</a> license.  However, a
215    license that requires modified versions to be nonfree does not qualify
216    as a free license.
217  </p>  </p>
218    
219  <p>  <p>
220  <q>Free software</q> does not mean <q>non-commercial.</q>  A free  The freedom to redistribute copies must include binary or executable
221  program must be available for commercial use, commercial development,  forms of the program, as well as source code, for both modified and
222  and commercial distribution.  Commercial development of free software  unmodified versions.  (Distributing programs in runnable form is necessary
223  is no longer unusual; such free commercial software is very important.  for conveniently installable free operating systems.)  It is OK if there
224    is no way to produce a binary or executable form for a certain program
225    (since some languages don't support that feature), but you must have the
226    freedom to redistribute such forms should you find or develop a way to
227    make them.
228  </p>  </p>
229    
230    <h4>Copyleft</h4>
231    
232  <p>  <p>
233  Rules about how to package a modified version are acceptable, if they  Certain kinds of rules about the manner of distributing free
234  don't substantively block your freedom to release modified versions, or  software are acceptable, when they don't conflict with the central
235  your freedom to make and use modified versions privately.  Rules that <q>if  freedoms.  For example, <a href="/copyleft/copyleft.html">copyleft</a>
236  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,
237  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.
238  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
239  at all.)  Rules that require release of source code to the users for  protects them.
 versions that you put into public use are also acceptable.  It is also  
 acceptable for the license to require that, if you have distributed a  
 modified version and a previous developer asks for a copy of it, you  
 must send one, or that you identify yourself on your modifications.  
240  </p>  </p>
241    
242  <p>  <p>
243  In the GNU project, we use  In the GNU project, we use copyleft to protect the four freedoms
244  <q><a href="/copyleft/copyleft.html">copyleft</a></q>  legally for everyone.  We believe there are important reasons why
245  to protect these freedoms legally for everyone.  But  <a href="/philosophy/pragmatic.html">it is better to use
246  <a href="/philosophy/categories.html#Non-CopyleftedFreeSoftware">non-copylefted  copyleft</a>.  However,
247  free software</a> also exists.  We believe there are important reasons why  <a href="/philosophy/categories.html#Non-CopyleftedFreeSoftware">
248  <a href="/philosophy/pragmatic.html"> it is better to use copyleft</a>,  noncopylefted free software</a> is ethical
249  but if your program is non-copylefted free software, we can still  too.  See <a href="/philosophy/categories.html">Categories of Free
250  use it.  Software</a> for a description of how &ldquo;free software,&rdquo;
251    &ldquo;copylefted software&rdquo; and other categories of software
252    relate to each other.
253  </p>  </p>
254    
255    <h4>Rules about packaging and distribution details</h4>
256    
257  <p>  <p>
258  See <a href="/philosophy/categories.html">Categories of Free Software</a>  Rules about how to package a modified version are acceptable,
259  for a description of how <q>free software,</q> <q>copylefted software</q>  if they don't substantively limit your freedom to release modified
260  and other categories of software relate to each other.  versions, or your freedom to make and use modified versions privately.
261    Thus, it is acceptable for the license to require that you change the
262    name of the modified version, remove a logo, or identify your
263    modifications as yours.  As long as these requirements are not so
264    burdensome that they effectively hamper you from releasing your
265    changes, they are acceptable; you're already making other changes to
266    the program, so you won't have trouble making a few more.
267  </p>  </p>
268    
269  <p>  <p>
270    Rules that &ldquo;if you make your version available in this way, you
271    must make it available in that way also&rdquo; can be acceptable too,
272    on the same condition.  An example of such an acceptable rule is one
273    saying that if you have distributed a
274    modified version and a previous developer asks for a copy of it, you
275    must send one.  (Note that such a rule still leaves you the choice of
276    whether to distribute your version at all.)  Rules that require release
277    of source code to the users for versions that you put into public use
278    are also acceptable.
279    </p>
280    
281    <p>
282    A special issue arises when a license requires changing the name by
283    which the program will be invoked from other programs.  That
284    effectively hampers you from releasing your changed version so that it
285    can replace the original when invoked by those other programs.  This
286    sort of requirement is acceptable only if there's a suitable aliasing
287    facility that allows you to specify the original program's name as an
288    alias for the modified version.</p>
289    
290    <h4>Export regulations</h4>
291    
292    <p>
293  Sometimes government <a id="exportcontrol">export control regulations</a>  Sometimes government <a id="exportcontrol">export control regulations</a>
294  and trade sanctions can constrain your freedom to distribute copies of  and trade sanctions can constrain your freedom to distribute copies of
295  programs internationally.  Software developers do not have the power to  programs internationally.  Software developers do not have the power to
296  eliminate or override these restrictions, but what they can and must do  eliminate or override these restrictions, but what they can and must do
297  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
298  way, the restrictions will not affect activities and people outside the  way, the restrictions will not affect activities and people outside the
299  jurisdictions of these governments.  jurisdictions of these governments.  Thus, free software licenses
300    must not require obedience to any nontrivial export regulations as a
301    condition of exercising any of the essential freedoms.
302  </p>  </p>
303    
304  <p>  <p>
305    Merely mentioning the existence of export regulations, without making
306    them a condition of the license itself, is acceptable since it does
307    not restrict users.  If an export regulation is actually trivial for
308    free software, then requiring it as a condition is not an actual
309    problem; however, it is a potential problem, since a later change in
310    export law could make the requirement nontrivial and thus render the
311    software nonfree.
312    </p>
313    
314    <h4>Legal considerations</h4>
315    
316    <p>
317    In order for these freedoms to be real, they must be permanent and
318    irrevocable as long as you do nothing wrong; if the developer of the
319    software has the power to revoke the license, or retroactively add
320    restrictions to its terms, without your doing anything wrong to give
321    cause, the software is not free.
322    </p>
323    
324    <p>
325    A free license may not require compliance with the license of a
326    nonfree program.  Thus, for instance, if a license requires you to
327    comply with the licenses of &ldquo;all the programs you use&rdquo;, in
328    the case of a user that runs nonfree programs this would require
329    compliance with the licenses of those nonfree programs; that makes the
330    license nonfree.
331    </p>
332    
333    <p>
334    It is acceptable for a free license to specify which jurisdiction's
335    law applies, or where litigation must be done, or both.
336    </p>
337    
338    <h4>Contract-based licenses</h4>
339    
340    <p>
341  Most free software licenses are based on copyright, and there are limits  Most free software licenses are based on copyright, and there are limits
342  on what kinds of requirements can be imposed through copyright.  If a  on what kinds of requirements can be imposed through copyright.  If a
343  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 345  is unlikely to have some other sort of p
345  (though this does happen occasionally).  However, some free software  (though this does happen occasionally).  However, some free software
346  licenses are based on contracts, and contracts can impose a much larger  licenses are based on contracts, and contracts can impose a much larger
347  range of possible restrictions.  That means there are many possible ways  range of possible restrictions.  That means there are many possible ways
348  such a license could be unacceptably restrictive and non-free.  such a license could be unacceptably restrictive and nonfree.
349  </p>  </p>
350    
351  <p>  <p>
# Line 184  We can't possibly list all the ways that Line 353  We can't possibly list all the ways that
353  contract-based license restricts the user in an unusual way that  contract-based license restricts the user in an unusual way that
354  copyright-based licenses cannot, and which isn't mentioned here as  copyright-based licenses cannot, and which isn't mentioned here as
355  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
356  it is non-free.  it is nonfree.
357  </p>  </p>
358    
359    <h4>Use the right words when talking about free software</h4>
360    
361  <p>  <p>
362  When talking about free software, it is best to avoid using terms  When talking about free software, it is best to avoid using terms
363  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
364  the issue is about price, not freedom.  Some common terms such  the issue is about price, not freedom.  Some common terms such
365  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
366  <a href="/philosophy/words-to-avoid.html">Confusing Words and Phrases that  <a href="/philosophy/words-to-avoid.html">Confusing Words and Phrases that
367  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
368  a list of <a href="/philosophy/fs-translations.html">translations of  a list of proper <a href="/philosophy/fs-translations.html">translations of
369  <q>free software</q></a> into various languages.  &ldquo;free software&rdquo;</a> into various languages.
370  </p>  </p>
371    
372    <h4>How we interpret these criteria</h4>
373    
374  <p>  <p>
375  Finally, note that criteria such as those stated in this free software  Finally, note that criteria such as those stated in this free software
376  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 385  a conclusion about a new issue, we often
385  it easier to see why certain licenses do or don't qualify.  it easier to see why certain licenses do or don't qualify.
386  </p>  </p>
387    
388    <h4>Get help with free licenses</h4>
389    
390  <p>  <p>
391  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
392  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 396  listed there, you can ask us about it by
396  </p>  </p>
397    
398  <p>  <p>
399  If you are contemplating writing a new license, please contact the FSF  If you are contemplating writing a new license, please contact the
400  by writing to that address. The proliferation of different free software  Free Software Foundation first by writing to that address. The
401  licenses means increased work for users in understanding the licenses;  proliferation of different free software licenses means increased work
402  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
403  meets your needs.  find an existing free software license that meets your needs.
404  </p>  </p>
405    
406  <p>  <p>
407  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
408  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
409  and avoid various practical problems.  and avoid various practical problems.
410  </p>  </p>
411    
412  <h2 id="beyond-software">Beyond Software</h2>  <h3 id="beyond-software">Beyond Software</h3>
413    
414  <p>  <p>
415  <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 421  manuals are in effect part of the softwa
421  The same arguments also make sense for other kinds of works of  The same arguments also make sense for other kinds of works of
422  practical use &mdash; that is to say, works that embody useful knowledge,  practical use &mdash; that is to say, works that embody useful knowledge,
423  such as educational works and reference  such as educational works and reference
424  works.  <a href="http://wikipedia.org">Wikipedia</a> is the best known  works.  <a href="http://wikipedia.org">Wikipedia</a> is the best-known
425  example.  example.
426  </p>  </p>
427    
# Line 256  has been extended to a definition of <a Line 431  has been extended to a definition of <a
431  free cultural works</a> applicable to any kind of works.  free cultural works</a> applicable to any kind of works.
432  </p>  </p>
433    
434  <h2 id="open-source">Open Source?</h2>  <h3 id="open-source">Open Source?</h3>
435    
436  <p>  <p>
437  Another group has started using the term <q>open source</q> to mean  Another group uses the term &ldquo;open source&rdquo; to mean
438  something close (but not identical) to <q>free software.</q>  We  something close (but not identical) to &ldquo;free software&rdquo;.  We
439  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
440  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
441  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">
442  never refers to freedom</a>.  never refers to freedom</a>.
443  </p>  </p>
   
444  </div>  </div>
445    
446    <h3 id="History">History</h3>
447    
448  <!--#include virtual="/server/footer.html" -->  <p>From time to time we revise this Free Software Definition.  Here is
449    the list of substantive changes, along with links to show exactly what
450    was changed.</p>
451    
452    <ul>
453    
454    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.162&amp;r2=1.163">Version
455    1.163</a>: Clarify that the four freedoms apply to any and all users,
456    and that requiring users to pay to exercise some of these freedoms is
457    a way of denying them.</li>
458    
459    <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
460    1.153</a>: Clarify that freedom to run the program means nothing stops
461    you from making it run.</li>
462    
463    <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
464    1.141</a>: Clarify which code needs to be free.</li>
465    
466    <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
467    1.135</a>: Say each time that freedom 0 is the freedom to run the program
468    as you wish.</li>
469    
470    <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
471    1.134</a>: Freedom 0 is not a matter of the program's functionality.</li>
472    
473    <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
474    1.131</a>: A free license may not require compliance with a nonfree license
475    of another program.</li>
476    
477    <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
478    1.129</a>: State explicitly that choice of law and choice of forum
479    specifications are allowed.  (This was always our policy.)</li>
480    
481    <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
482    1.122</a>: An export control requirement is a real problem if the
483    requirement is nontrivial; otherwise it is only a potential problem.</li>
484    
485    <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
486    1.118</a>: Clarification: the issue is limits on your right to modify,
487    not on what modifications you have made.  And modifications are not limited
488    to &ldquo;improvements&rdquo;</li>
489    
490    <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
491    1.111</a>: Clarify 1.77 by saying that only
492    retroactive <em>restrictions</em> are unacceptable.  The copyright
493    holders can always grant additional <em>permission</em> for use of the
494    work by releasing the work in another way in parallel.</li>
495    
496    <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
497    1.105</a>: Reflect, in the brief statement of freedom 1, the point
498    (already stated in version 1.80) that it includes really using your modified
499    version for your computing.</li>
500    
501    <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
502    1.92</a>: Clarify that obfuscated code does not qualify as source code.</li>
503    
504    <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
505    1.90</a>: Clarify that freedom 3 means the right to distribute copies
506    of your own modified or improved version, not a right to participate
507    in someone else's development project.</li>
508    
509    <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
510    1.89</a>: Freedom 3 includes the right to release modified versions as
511    free software.</li>
512    
513    <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
514    1.80</a>: Freedom 1 must be practical, not just theoretical;
515    i.e., no tivoization.</li>
516    
517    <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
518    1.77</a>: Clarify that all retroactive changes to the license are
519    unacceptable, even if it's not described as a complete
520    replacement.</li>
521    
522    <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
523    1.74</a>: Four clarifications of points not explicit enough, or stated
524    in some places but not reflected everywhere:
525    <ul>
526    <li>"Improvements" does not mean the license can
527    substantively limit what kinds of modified versions you can release.
528    Freedom 3 includes distributing modified versions, not just changes.</li>
529    <li>The right to merge in existing modules
530    refers to those that are suitably licensed.</li>
531    <li>Explicitly state the conclusion of the point about export controls.</li>
532    <li>Imposing a license change constitutes revoking the old license.</li>
533    </ul>
534    </li>
535    
536    <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
537    1.57</a>: Add &quot;Beyond Software&quot; section.</li>
538    
539    <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
540    1.46</a>: Clarify whose purpose is significant in the freedom to run
541    the program for any purpose.</li>
542    
543    <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
544    1.41</a>: Clarify wording about contract-based licenses.</li>
545    
546    <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
547    1.40</a>: Explain that a free license must allow to you use other
548    available free software to create your modifications.</li>
549    
550    <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
551    1.39</a>: Note that it is acceptable for a license to require you to
552    provide source for versions of the software you put into public
553    use.</li>
554    
555    <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
556    1.31</a>: Note that it is acceptable for a license to require you to
557    identify yourself as the author of modifications.  Other minor
558    clarifications throughout the text.</li>
559    
560    <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
561    1.23</a>: Address potential problems related to contract-based
562    licenses.</li>
563    
564    <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
565    1.16</a>: Explain why distribution of binaries is important.</li>
566    
567    <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
568    1.11</a>: Note that a free license may require you to send a copy of
569    versions you distribute to previous developers on request.</li>
570    
571    </ul>
572    
573    <p>There are gaps in the version numbers shown above because there are
574    other changes in this page that do not affect the definition or its
575    interpretations.  For instance, the list does not include changes in
576    asides, formatting, spelling, punctuation, or other parts of the page.
577    You can review the complete list of changes to the page through
578    the <a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;view=log">cvsweb
579    interface</a>.</p>
580    
581    <h3 style="font-size:1em">Footnote</h3>
582    <ol>
583    <li id="f1">The reason they are numbered 0, 1, 2 and 3 is historical. Around
584    1990 there were three freedoms, numbered 1, 2 and 3. Then we realized that
585    the freedom to run the program needed to be mentioned explicitly.
586    It was clearly more basic than the other three, so it properly should
587    precede them. Rather than renumber the others, we made it freedom&nbsp;0.</li>
588    </ol>
589    
590    </div><!-- for id="content", starts in the include above -->
591    <!--#include virtual="/server/footer.html" -->
592  <div id="footer">  <div id="footer">
593    <div class="unprintable">
594    
595  <p>  <p>Please send general FSF &amp; GNU inquiries to
596  Please send FSF &amp; GNU inquiries to  <a href="mailto:gnu@gnu.org">&lt;gnu@gnu.org&gt;</a>.
597  <a href="mailto:gnu@gnu.org"><em>gnu@gnu.org</em></a>.  There are also <a href="/contact/">other ways to contact</a>
598  There are also <a href="http://www.fsf.org/about/contact.html">other ways to contact</a>  the FSF.  Broken links and other corrections or suggestions can be sent
599  the FSF.  to <a href="mailto:webmasters@gnu.org">&lt;webmasters@gnu.org&gt;</a>.</p>
600  <br />  
601  Please send broken links and other corrections (or suggestions) to  <p><!-- TRANSLATORS: Ignore the original text in this paragraph,
602  <a href="mailto:webmasters@gnu.org"><em>webmasters@gnu.org</em></a>.          replace it with the translation of these two:
603  </p>  
604            We work hard and do our best to provide accurate, good quality
605            translations.  However, we are not exempt from imperfection.
606            Please send your comments and general suggestions in this regard
607            to <a href="mailto:web-translators@gnu.org">
608            &lt;web-translators@gnu.org&gt;</a>.</p>
609    
610            <p>For information on coordinating and submitting translations of
611            our web pages, see <a
612            href="/server/standards/README.translations.html">Translations
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614    Please see the <a
615    href="/server/standards/README.translations.html">Translations
616    README</a> for information on coordinating and submitting translations
617    of this article.</p>
618    </div>
619    
620  <p>  <!-- Regarding copyright, in general, standalone pages (as opposed to
621  Please see the       files generated as part of manuals) on the GNU web server should
622  <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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630         years, as long as each year in the range is in fact a copyrightable
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632         being publicly visible on the web or in a revision control system).
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636    
637    <p>Copyright &copy; 1996, 2002, 2004-2007, 2009-2019
638    Free Software Foundation, Inc.</p>
639    
640    <p>This page is licensed under a <a rel="license"
641    href="http://creativecommons.org/licenses/by-nd/4.0/">Creative
642    Commons Attribution-NoDerivatives 4.0 International License</a>.</p>
643    
644  <p>  <!--#include virtual="/server/bottom-notes.html" -->
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645    
646  <p>  <p class="unprintable">Updated:
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647  <!-- timestamp start -->  <!-- timestamp start -->
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650  </p>  </p>
651  </div>  </div>
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