Ogre Forums

Some of our users have been discussing Qt licensing recently and they've hit upon a fairly serious problem. Obviously the switch to the LGPL is a good thing for them, but as they began to explore they encountered this clause in the commercial license terms (emphasis mine):

"You must purchase a Qt Commercial License from us or from one of our authorized resellers before you start developing commercial software. The Commercial license does not allow the incorporation of code developed with the Qt GNU LGPL v. 2.1 or GNU GPL v. 3.0 license versions into a commercial product."

This made no sense at all to our community members. Here's what happen's in real-life with open source libraries which have a dual-license structure:

1. Team start developings an application which they think they might make commercial later, but maybe they're not sure, or they're not sure precisely of the form that will take
2. In the early stages, perhaps while in incubation or while prototyping, team evaluates and tries out a number of libraries. Normally, open source licenses like the GPL and LGPL do not require any specific actions on the part of the developer, unless they distribute the end results (which at this stage, they haven't yet). The focus is on startup tasks, not finalising a license model.
3. Later on when their commercial plans firm up, they'll decide whether they need to license some of these open source libraries under an alternative license or not. Usually there are a couple of variants, either:
- 1. They make the decision before they distribute any copies of the software, so they haven't at that stage needed to take any action to comply with the LGPL/GPL, so will buy an alternative license in order to start distribution, or
- 2. They decide later on, after distributing under and complying with the open source license, that they want to offer a different version of their software (maybe a version 2.0, or a premium edition) under alternative terms, for which they need to purchase an alternative license

It is *extremely* common for people to make these decisions some way into the development. It's very, very uncommon for people to make firm decisions before they write a single line of code, because they don't know before they at least build a proof of concept whether this is the route for them. The whole point of open source is that it's perfect for prototyping and trying out ideas before committing to a business model. Therefore, the Qt commercial license clause is completely at odds with the way these things usually work. Essentially it's asking people to decide long before they're ready.

So, because of this we're getting a lot of concern in the community. People who are 100% happy with the LGPL aren't concerned, but those who like to keep their options open will find that clause a deal-breaker. What is the reasoning behind it, and can it be changed?

PolyVox wrote:For example, a company could have many developers working with the LGPL version and then by a single commercial license so that they can claim support.