Do open source copyrights/licences expire? [closed]

Question

This is a purely hypothetical question, but current copyright in the U.S. is life + 70 (I think).

Some open source licences require derivative works to also be open source.

My question is, are programmers no longer required to open source the derivative code if the license expires? How about in other countries where the copyright term may be shorter?

Answer 1

Copyright, in theory, expires. At that time the work, if not renewed or updated, would fall into the public domain.

However:

1. The Mickey Mouse copyright extensions means that every time a key work would enter the public domain, copyright terms are extended.
2. Software from as little as 10 years ago in general is not relevant - things move to fast.

Answer 2

I am not a lawyer (IANAL) but my understanding is that copyright is completely unrelated to open source licensing. Under US law, the author of a literary or other creative work automatically has copyright protection of their work. No declarations or registrations are required. That copyright may expire some period of time after the author of the work is deceased. I'm not clear on the details, and the fact that the "Micky Mouse" copyright extensions keep changing that limit doesn't help clarity.

Open source licensing is not a right, it is a license that specifies the terms and conditions under which the source code may be used. The author decides what license terms to release the source code under, and the licensees (consumers of that source code) are held to that license. If the author's code is based upon a prior work, the author's license term options may be restricted by the license of the prior work.

I'm not aware of any expiration date associated with licenses. They are essentially contracts, so unless the contract/license explicitly states an expiration scenario, the license terms are in force forever.