The main difference for the potential embedded user base is that LGPLv3 makes explicit (rather than implicit) that users must be able to run custom code (= modified qt) on the embedded devices; if your device is locked down (e.g.: no possibility to do firmware upgrades, or digital signature checks), you must buy a commercial license.
This is true for applications that use the new LGPLv3-only modules. For applications using LGPLv2.1 modules, you can still try to freeload by sticking to a literal reading of the license, though I would personally advise against it.
(Sorry, I miss clicked and deleted the wrong comment. Here is it but in wrong order.)
Actually, if the device has no possibility to do firmware upgrades, then that is in compliance with the the license.
GPL has an exception which say that the requirement "does not apply if neither you nor any third party retains the ability to install modified object code on the User Product (for example, the work has been installed in ROM)".
The goal is that "modified object code is in no case prevented or interfered with solely because modification has been made". It is targeting the intentional anti-consumer and anti-property design in which the manufactorer retain control of the device, after sale. If you don't intentionally prevent others from modifying the device, then the product is unlikely to be effected by the license requirement.
(The quoted parts are directly taken from the GPL license text, section 6).
Why not? If they have problems with code sharing, they can still touch it like they could always do: buy an exception.
I'm surprised that LGPL exceptions are a good way to make money, but this v2.1 -> v3 change doesn't change a lot of Digia's exception-selling business.
Selling GPL exceptions make more sense to me, whereas LGPL exceptions are still a bit more mysterious, but I guess they both work.
Blizzard used LGPL software in starcraft 2, the fastest selling real-time strategy game of all time.
But I guess, they should have avoided LGPL, delayed sale, and increased production cost. Thats how companies that want to earn money should behave, right?
Why? They have just added an licensing option to a set of existing ones. LGPLv2.1 and proprietary commercial licensing are still here for anyone who wish to restrict their users.
No, no, I thought that too, but it's not like that.
They are adding some new modules that are LGPLv3 only. The old ones are LGPLv2.1, with an option to use LGPLv3, I assume. Hard to tell from their description without reading the legalese, but they'll need something like it, because v2.1 and v3 are incompatible with each other.
Technically, what it means is that you need to sell the app and an offer for the source code. It might be semantics, but it's not really accurate to say you have to "give the source away" -- you could also say that you sell access to the source and give away the binary as an added service...
> Technically, what it means is that you need to sell the app and an offer for the source code.
Only for the library (and any modifications to it), not the app itself.
If the developer makes modifications to the actual source code of Qt itself he/she has to release those modifications[0]. He/she does not have to release the rest of the source code of the app.
[0] Technically, the Qt source must be provided whether or not any modifications were made, though this is easily fulfilled.
For iOS there never was a free option, one has to buy the commercial version. For Android it should work just the same as before as far as I can determine (but I might be wrong).
All the more reason not to use them so widely. They sometimes are invasive and behave like a virus (GPLv3).
PyQt4 vs pyside is a good example of licensing done wrong, I am not sure licensing a library under GPL would help others as it restricts the projects using them to use only GPL. It means that if you just link to it (just use the names in your program and rely on the client to have installed the right library) then your project needs to be at least the same version of GPL.
Then we have pyside who reinvents the wheel for people who cannot afford to pay for a simple layer between python and qt4.
LGPL is fine though for such uses.
But the main point I want to make is that people using those license seldom read them entirely, which makes it actually a big show stopper and ruin their effort to help the community.
There is this loud minority that only find value in software if they can slap some restrictions on it, and then get upset that GPL won't allow it.
That people can be so self-absorbed that they can't enjoy being given software for free is sad. It is also harming the community, and ruining the work of so many people.
This is true for applications that use the new LGPLv3-only modules. For applications using LGPLv2.1 modules, you can still try to freeload by sticking to a literal reading of the license, though I would personally advise against it.