Q Public License Version 1.0 (QPL)

I. Overview

A Norwegian technology company – Trolltech, drafted the QPL. The main goal of the QPL is to provide an open source licensing model for the public to freely share and use software. The QPL is based on the Trolltech’s Qt software design platform. Since the QPL is specifically designed for Qt, one shall not leave Qt out of consideration when trying to analyze rights and duties stipulated by the QPL. Rather, the market share and development of Qt shall all be taken into account in order to have more compressive understanding.

II. Current Status

The current status of the QPL is a somewhat contradictory situation. It still enjoys quite a market share for the proportion of users, but only for a historical reason. Qt-based KDE still plays a very important role in the desktop environment for Linux. Additionally, there are also numerous softwares written based on Qt. However, whether the current status will remain like this is questionable. According to the official website of Trolltech, instead of its own QPL, its new version of Qt is licensed under a “dual licensing model”. The so-called dual licensing model allows both the GPL and commercial licenses. The first reason is compability—that since the GPL has the largest market share, softwares licensed under the GPL will have a better chance of being compatible with others, and this will be of great advantages to the Qt community. Secondly, the “report to the original copyright holder of any modification or addition” clause can now be replaced with the dual licensing model. In summary, the QPL is still very important for its historical position, but may be replaced gradually in the future.

III. Rights and Duties

Only the main rights and duties are listed in the following. A full context of the QPL and consultations are needed if further information is requested. Programs licensed under the QPL are referred to as Q-software, and programs added or modified are called patches in what follows. This is also a main feature of the QPL, namely that no one is entitled to modify the body of the software except the original copyright holder. To customerize the software, additions or deletions must be made with patches.

  1. Rights

    (1) The licensee may copy and distribute the Q-software in unmodified form, including but not limited to copyright, trademark notices and disclaimers, as released by the initial developer of the software, is distributed. The licensee is not granted any right to add, delete or modify the original body of the program.

    (2) The licensee may make modifications to the Q-software, in a form that is separate from the software, such as patches. Note that none addition, delectation or modification may be made to the original body of the program.

    (3) The licensee may use the original or modified versions of the Q-software, which means to have links or to run application programs with other software, but not to combine them physically.

    (4) The licensee may develop application programs and other software items that link with the original or modified versions of the Q-software or patches.

  2. Duties

    (1) Patches written based on Q-software must be provided to the Q-software, as a reference for the updates of Q-software. Notice that modifications may neither alter nor remove any copyright notices in the Q-software to warrant the quality.

    (2) Q-software or the patches may be distributed only in machine-executable forms, provided that the complete machine-readable source code is also available to all recipients, without any charge beyond the costs of data transfer.

    (3) Q-software or the patches may be distributed separately in machine-executable and source code forms, provided that this license document is included in the distribution. Furthermore, the complete machine-readable source code must also be available to all recipients, without any charge beyond the costs of data transfer.

    (4) When the licensee develops application programs and other software items that link with the original or modified versions of the Q-software and distribute them to the public, the machine-executable code and complete machine-readable source code must both be available to all recipients, without any charge beyond the costs of data transfer.

    (5) What is noteworthy is if the above-mentioned items are not available to the general public, but the initial developer (and original copyright holder) of the Q-software requests a copy of the items, then the licensee must supply one.

IV. Unique Features

From the literal expression, the most unique feature of the QPL is this license is governed by the Laws of Norway and disputes shall be settled by Oslo City Court. This feature is a reflection of what mentioned before, namely the QPL is specifically designed for the Qt software. What seems like an open source strategy may actually have deep business implications. In details, it can be elaborated with a few more comments.

  1. Any modification or contribution to Q-software must come back to the original copyright holder. He can request a copy of the modified source code from the later developer, even if the items are not available to the general public. This clause is unseen in any other licenses.

  2. Modifications to Q-software must be made in an independent patch form, and not in the original body of the Q-software. This is to protect the original copyright holder’s reputation and avoid any unnecessary accompanying duties.