I'm currently programming a Flutter mobile app and a website. I use code from the MIT license on the website and the app. In the app I also use code under the Apache 2.0 license and the BSD 3 clause.
I am modifying all of these codes. Some more and some less.

Is it allowed, if I have the licenses and copyright notices correctly in my project, NOT to add a comment or mark the modifications that I made?

This question relates to all 3 licenses

1 Answer 1


You should add e.g. "(c) 2021 Joe R. User" to the file headers (where you find such comments) to mark that you've made some changes, and claim your rights to them formally.

Check the licenses. They don't ask to mark any changes you do, so you don't have to do so.

But think of your gentle reader, a few years down the road and half a world distant (or even yourself, in a few weeks ;-): You want them to understand what is going on, perhaps do some changes in a different way or elide them altogether. Today presumably you keep the code under some version control system like git or hg. Make small, self-contained changes (not "weekly dump of changes"), write clear commit messages (not "Updated", "New version"), perhaps add in a Changelog file with an overview of changes. Import any upstream packages marking their origin, version and so on clearly. If you update the base package, mark any relevant import commits clearly as such.

Think of any would-be user: Make sure to chase down any licenses that apply, record your findings and keep copies of the licenses at hand. This is also important for your protection: it isn't fun to get sued for inadvertently violating some license or software patent.

  • 1
    Yes, but you should or must indicate that you made changes; doing so in the copyright notice is one way and suffices. Yet without any indication whatsoever, the original authors might have recourse that you mis-represent their work and slander their good name, if you distribute modified code without indicating in any way that you modified it. Jun 22, 2021 at 15:05
  • I think that you are not obliged to indicate your own copyright and therefore I think that it would be enough to mark the changed code snippets. If you would keep the code closed source you don't have to do any of that, right? Jun 22, 2021 at 19:27
  • @VincentMusk, wether the code is open for all to see or closed doesn't really matter in much of my advise: somebody will have to make sense of it all later on. Most of the time that will be you ("You wrote it, so you'd be in the best position to..."), do yourself a huge favour. (Yes, that I learned the hard way,)
    – vonbrand
    Jun 23, 2021 at 0:13
  • But I don’t have to do that. Jun 23, 2021 at 7:33
  • @planetmaker You say that you "must" indicate that you made changes. I don't see that in the license text. Jun 23, 2021 at 7:37

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