According to Wikipedia's Copyright Formalities and Copyright notice, dating or even putting the author copyright notice in unnecessary.

And then explanations such as this Stack Overflow Post make me wonder about how redundant dating is.

Except maybe to show when the work was start or published, what is the point of the date?

Also how strict is GPL on including dates and date ranges? The FSF website says to use ranges but they just seem like a formality.



If you look at there licenses, you will notice that the following text appears near the end of page.


That is the end of the license. Nowhere above that text is there a requirement to add the year to the copyright notice. However, as pointed out in Stephen Kitt's answer, if you modify somebody else's program GPLv3 section 5 requires you to include a prominent notices stating that you modified it, with a date.

This requirement to record the date for changes you make to somebody else's program is to make sure that downstream recipients is made aware of modifications of the chronology and history of changes made to the original source code.

By law, your copyright is valid without a copyright notice (at least in Berne signatories, including the USA) - but if you leave it out (the notice, not the year), you may need to assert your copyright by other means if your copyright is challenged.

Going back to the web pages with the A(GPL) licenses, notice that below the "END OF TERMS AND CONDITIONS", there is a new headline:

How to Apply These Terms to Your New Programs

This is a helpful guideline - not a license requirement. Your license, and your copyright, is valid even if you choose to not follow this guideline.

However, it is a good idea to have a copyright notice with the year of publication. While not legally required, having such a notice in place may save you from proving that you've asserted your copyright by other means in the case of a dispute, and damages awarded may be reduced if there is no copyright notice in your work.

  • "Nowhere above that text is there a requirement to add the year" – yes there is, in section 5 as @StephenKitt's answer highlights. Jul 22 '15 at 13:31
  • @AbhiBeckert. You quote out of context. The full sentence reads: "Nowhere above that text is there a requirement to add the year to the copyright notice." So the paragraph you refer to has nothing to do with the copyright notice. It is to inform downstream recipients about modifications to the original source code. Jul 22 '15 at 14:02
  • The question is wether or not it's mandatory to include dates in GPL licensed code. And the answer is a clear yes as I see it, even though you're not required to put those dates as part of a copyright notice. Jul 22 '15 at 14:10
  • I think you should edit your answer to cover that part of the license and make it clear that anyone who contributes to GPL'd code does need to include a note about the date they worked on it. As your answer stands now, you're implying (by omission) that GPL doesn't require dates. Jul 22 '15 at 14:12
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    @AbhiBeckert. Done. Jul 22 '15 at 14:16

It depends...

You're right in that adding a copyright statement doesn't add anything to the default protection you get under copyright law. But it is useful for documentation purposes; see Should I include a copyright line in every file? for more on that.

As far as licenses are concerned, some do require that dates be mentioned in some cases. For example, in version 3 of the GPL, section 5 (regarding modified source versions) says

a) The work must carry prominent notices stating that you modified it, and giving a relevant date.

This doesn't require that the information be present in a copyright statement, but adding a copyright statement is the easiest way of doing so.

  • Will one date be sufficient for thereafter or is it a date per change? The former seems more reasonable.
    – user374
    Jul 22 '15 at 15:11
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    I'm guessing a single date is sufficient to satisfy the license's terms. If you look at most software projects you'll see dates are rarely updated properly, even when companies are involved! Jul 22 '15 at 18:36

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