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LGPL

Critique: Guide to the Total Cost of Ownership of Open-Source Software

The post Guide to the Total Cost of Ownership of Open-Source Software by Peter Schneider (The Qt Company) provides a smorgasbord of alternative facts why we should not use Qt LGPL but instead buy Qt Commercial. I can’t miss the irony that Schneider like many of his sales colleagues are bad-mouthing Qt LGPL to promote Qt Commercial. Qt LGPL and Commercial share the same code.

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Using Qt 5.15 and Qt 6 under LGPLv3

Nearly exactly 5 years ago, I wrote my first article about Using Qt 5.6 and Later under LGPL. The trigger then was the switch from LGPLv2.1 to LGPLv3 with Qt 5.6. The trigger now is the switch from Qt 5 to Qt 6. All the Qt modules under LGPLv3 5 years ago are still available under LGPLv3 – unless they have been retired. Some new modules like Charts, CoAP and MQTT were only available under Qt Commercial until Qt 5.15, but are now available under the new Marketplace license for 50-300 USD per year (no royalties). Some new modules like Quick 3D and WebAssembly are only commercially available. All in all not much changed: You can still build fantastic HMIs with Qt LGPLv3.

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FOSS Qt Releases Delayed by up to 12 Months?

On 8 April 2020, Olaf Schmidt-Wischhöfer wrote in an email to the KDE community (emphasis mine):

[…] last week, [The Qt Company] suddenly informed both the KDE e.V. board and the KDE Free QT Foundation that the economic outlook caused by the Corona virus puts more pressure on them to increase short-term revenue. As a result, they are thinking about restricting ALL Qt releases to paid license holders for the first 12 months.

To be clear: Nothing has been decided yet. I certainly hope that this “thinking” by The Qt Company remains just that: thinking. But I am not quite sure.

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Less Love for FOSS Qt Users

From Qt 5.15, The Qt Company make their offering a bit more inconvenient for FOSS users. They announced three changes:

  • A Qt account is mandatory to download binary Qt packages. The offline installer is not available to FOSS users any more.
  • LTS (long-term support) releases are not available to FOSS users, once the next minor or major release is out.
  • Small business pay 499 USD per year, if their yearly revenue is less than 100,000 USD and they have less than five employees.

What do these changes mean for the development of Qt embedded Linux systems under LGPLv3?

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Safe-Guarding the (L)GPL Future of Qt

The little known KDE Free Qt Foundation makes sure that Qt stays free and open-source. It guarantees that all Qt modules currently licensed under LGPLv3 must continue to be available under LGPLv3 in the future. This covers all modules from Qt Essentials and many add-on modules. If The Qt Company discontinued the FOSS version of Qt, the Foundation would have the right to make Qt available under the BSD license. This is a very powerful protection of free and open-source Qt.

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Using Qt under LGPLv3

At Qt Day 2019 in Florence, Italy, I gave a talk Using Qt under LGPLv3. In the first part The obligations of Qt LGPLv3: made understandable, I explain in detail, how you must provide the source code, the license texts, the copyright notices, any modification notices and the installation information. You don’t have to provide the installation information for B2B products like driver terminals in commercial vehicles, industrial devices and medical devices in hospitals. In other words, you don’t have to satisfy the anti-tivoisation rule for B2B products.

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Seminar “Open-Source Management in Software Supply Chains”

On 20 November 2018, the law firm Bird & Bird hosted a seminar about “Open-Source Management in Software Supply Chains – Effective and Consistent License Compliance” in their Frankfurt office. The seminar was organised by Miriam Ballhausen, who is Bird & Bird’s specialist in open-source Licensing.

The seminar offered the opportunity to meet two of Germany’s top lawyers for FOSS license compliance: Miriam Ballhausen and Catharina Maracke. If you have any questions about how to comply with FOSS licenses, Miriam and Catharina will give you invaluable counsel.

The roughly 25 attendees hailed from very different industries: automotive, agricultural, financial, medical, manufacturing and IT services. In late 2018, you cannot escape FOSS: Free open-source software has arrived in the mainstream.

Now, let me give you a summary of the four talks.
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Using Qt 5.6 and Later under LGPL

Up to Qt 5.3, things were pretty simple. Most modules were under LGPLv2.1 with the exception of some commercial modules. Starting with Qt 5.4, new Qt modules were published under LGPLv3 and old modules additionally under LGPLv3. With Qt 5.6, we now have quite a patchwork of modules under different licenses. Qt 5.7 will drop LGPLv2.1 completely. Some companies stay on Qt 5.3, because they are afraid of LGPLv3. Let me bring some clarity into this patchwork and explain how you can still use Qt under LGPL and sleep well.
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