Is displaying Open Source License Acknowledgments legally mandatory?
<p>When a piece of software explicitly requires that their open source license acknowledgments be included in derivative software (software that uses the open source software), is this a legally enforceable requirement?</p>

<p>According to <a href="http://blog.human-friendly.com/are-you-breaching-open-source-licenses-accidentally" rel="nofollow">this blog post</a> it is, but let's look at an example. PayPal have an open source project, <strong>card.io</strong>, that third-party mobile app developers can use for scanning credit cards in their apps. They <a href="https://github.com/card-io/card.io-iOS-SDK" rel="nofollow">state</a>:</p>

<blockquote>
  <p>Add card.io's open source license acknowledgments to your app's acknowledgments.</p>
</blockquote>

<p>However, when I downloaded apps that use this project (Uber, PayPay itself, TaskRabbit, EAT24, grubHub, etc.), in some cases I found that they had a section on software licenses, however I did not find the license acknowledgments for <strong>card.io</strong> inside any of the apps (Uber is a good example of this).</p>

<p>What are the legal ramifications of not including the license acknowledgments in a visible part of the app (let's say it's a banking app here)? </p>

<p><strong>When a piece of software explicitly requires that their open source license acknowledgments be included in derivative software (software that uses the open source software), is this a legally enforceable requirement?</strong></p>

<p>Yes</p>

<p><strong>What are the legal ramifications of not including the license acknowledgments in a visible part of the app (let's say it's a banking app here)?</strong> </p>

<p>That would depend on if it was a requirement that the acknowledgement be publically accessible; it may be buried in a copyright notice in the source code. Remember, Copyright in software resides in the code, images and displays as "literary" works - algorithms are not subject to copyright.</p>

<p>If the person has breached the copyright licence then the copyright holder can take action against them. Normally such action would be a request to comply with the license followed by a cease and desist order.</p>

<p>In this case what action they want to take is up to PayPal or the copyright holder who granted the licence to them.</p>

<p>If the copyright holder states "you have the right to create derivative works of my software if you do X, Y and Z", and you don't do X, Y and Z, then creating a derivative work is copyright infringement. The copyright holder can sue you for copyright infringement. </p>

<p>The copyright holder cannot <em>force</em> you to do X, Y and Z. They can give you a hint that they wouldn't sue you for copyright infringement if you do X, Y and Z and that may be "an offer you cannot refuse". </p>

<p>You can <em>not</em> tell the court "I want to pay damages for breach of contract for not doing X, Y and Z" if that is cheaper. Say the license was "you can create a derivative work if you donate $10 to the Red Cross" you can't say the damage is just $10. You were offered a license for the cost of $10, you didn't take it, that's your own fault. You pay for copyright infringement. </p>

licensing intellectual-property