With conventional copyright, N years after the author's death the copyright expires (where N varies from country to country). Since free and open source licences are supported legally by copyright law, what happens N years after the original author's death? Does the project move from being free or open source to being public domain?

Does the result depend on who else contributed (since their copyright contributions will also be part of the overall project)? Do continuing contributions prevent the project from becoming public domain, or will those parts of the project contributed by people who have since died over N years ago become public domain, leaving the free or open source licence only applying to the more recent contributions?

3 Answers 3


The copyright on the combined work expires when the most recent part of the individual copyrights expires (in the US generally life + 70 years of the last author) and the project would enter the public domain.

Older parts of the project enter the public domain before the newer parts, and with that, the combined work do. It's possible for a combined work to have its older parts in the public domain, while its newer parts are still under copyright. In that case, you could use the older version as a public domain version.

For most software projects this is somewhat of a non-starter. life + 70 years is effectively forever. I don't have my crystal ball with me at the moment, but I don't suspect much software written now will still have applications in the year 2085.

  • 5
    I think your answer is good, but you should probably also cover the part of the question that ask if an older part can go public domain without newer contributions.
    – Mnementh
    Jun 28, 2015 at 20:46
  • Note that 70 years since the last contribution is likely substantially longer than 70 years from now, if the project receives enough attention to still exist at that time. Jun 24, 2022 at 22:19

In theory, a computer program whose copyright expires enters the public domain, which is largely equivalent to an all-permissive free software license without attribution, such as the WTFPL. But in practice, copyright in a computer program created since "free software" became a thing is unlikely to ever expire in most of the industrialized world, for reasons quite unrelated to computer programs.

Whenever copyright in works published in the mid-1920s is due to expire in the United States, two organizations* lobby for a retrospective copyright term extension in an industrialized jurisdiction not subject to a rule analogous to "for limited Times" rule of the U.S. Constitution. Then they lobby for "harmonization" bills in other countries. This most recently happened in the 1990s with the Copyright Duration Directive of 1993 in the European Union, followed by the Copyright Term Extension Act of 1998 in the United States. The music and film industry associations of America then proceed to push the newly "harmonized" term to the rest of the world through the U.S. Trade Representative.

"But what about copyrights in free software that have already expired?"
No copyright in a computer program published after the GNU Manifesto has expired. In fact, the vast majority of works by anyone who was alive to see ENIAC run are still under copyright. (The largest exception includes U.S. works published prior to 1964 whose copyright was not renewed in the 28th year.) This leaves pretty much Ada Lovelace's programs for Charles Babbage's Analytical Engine.

* These organizations are The Walt Disney Company and Gershwin Enterprises.


This depends widely on what is losing its copyright. But no matter what it is put into, people call the Public Domain. The public domain is just a fancy way of saying "it is now available to the public as a whole, and therefore not subject to copyright".

If the project was already open sourced basically nothing changes, except for whatever license was on it. Now ANYONE can do WHATEVER they want to it.

So technically the Open Source is lost but also it is still there because now ANYONE can build and improve upon it.

  • Is the Public Domain really a fancy way of saying that something is available to the public?
    – Zizouz212
    Jun 28, 2015 at 20:52
  • 2
    @Zizouz212 no, it means it's owned by the public, i.e. not owned by anyone in particular. Therefore copyright licenses like copyleft cannot be enforced. Jun 29, 2015 at 5:34

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