Boden author here, a bit overwhelmed by the feedback. We are in the process of releasing a new version that will change the license to LGPL / Commercial.
LGPL has the same problem! Users must be able to relink an application with their own version of the LGPL library. This is impossible for almost all iOS scenarios and only very slightly easier on Android.
This is often overlooked. If you want to keep LGPL you can investigate "linking exception", it's used by some GNU libraries if I recall correctly.
The GPL is not compatible with Apple's App Store restrictions, so giving away your source code is not sufficient to comply with the GPL.
"The primary problem is that Apple imposes numerous legal restrictions on use and distribution...through the iTunes Store Terms of Service, which is forbidden by section 6 of GPLv2."
There is also a significant difference between giving away free applications and giving away the source code. Both from an internal perspective (the company may want to charge for the product or related products or products on other platforms now or in the future) and an external perspective (the app may require other software for which the company does not have rights to release source code).
"Here's a free loaf of bread."
"Why don't you just give me the bread factory and the farms that supplied the ingredients?"
Maybe because some mega corp will figure out how to offer it as a service, and they'll get nothing for it. I support them defending themselves with a way to maybe make money on it. If they can't eat, they can't update the code.
So it's very conceivable that if your app is producing money for you, you don't want to open source the magic as it were - but if you're making money, you shouldn't expect a free ride.
However, if you aren't making money, and are still using the work of others, then it's good to contribute back - even if that's just by open sourcing your work for others to learn from and study. It's not required, but neither is it required for this framework to have a free tier, much less a truly free one that helps protect the future of your app.
Please take the following with a grain of salt. I am not a legal expert, but we have competent US lawyers assessing this for us right now.
The main issue we see with the GPL is that your app has to be effectively licensed under the GPL too, which makes your app's license incompatible with the iOS App Store's terms of service.
This is apparently not the case with the LGPL. Yes, you will have to provide a way for users to relink your application to another version of Boden. As far as I can see (I am not a lawyer), this can happen outside of the iOS App Store.
Our US lawyers are currently investigating this. As soon as we get a reliable assessment from the legal experts, we'll add an LGPL option to Boden.
LGPL 2.1 6c - on request, you provide the user with object code they can link against their custom version. Should be enough, if no other terms of the app store get in the way?
(VLC is an example of a well-known program that relicensed to LGPL and now is available in the app store, so clearly it is possible)
And how does the user then get their relinked app onto their phone?
(There are plenty of App Store apps with LGPL code in them. The question is, should they be there? And VLC is not a good example, since presumably, I don't know - but I think all of it is LGPL or in any case, open source. The user can rebuild all of VLC in that example. The situation with Boden is going to be that a an app, probably proprietary, has a Boden library in it.)
If the app is open source (or at least the source code is accessible), the user would proceed to the source repo, clone it, open the Xcode project and relink to the framework version of their choice.
Others have pointed out how it could work with closed source apps. It's a bit more complicated, but it certainly is possible.
It would be prudent to advertise this expectation of the app developer hoping to use the LGPL version. (Whereas with for instance the MPL and other licenses, no such need exists.)
Consider the Mozilla Public License (MPL) [1]. It is copyleft in the sense that modifications to the library must be MPL-licensed as well, but doesn't impose any restrictions on apps merely using the library. This avoids the LGPL’s complicated re-linking requirements which are very hard to fulfill for iOS apps (as mentioned elsewhere in this thread).
We have put a lot of effort into investigating and assessing different licensing options. There are two different perspectives on this: the user perspective where MIT of course seems to be among the most attractive ones at first glance. Then, there's the company perspective: what is the business model and how is development going to be sustainable in the long run?
We have come to the conclusion that LGPL is currently the best option to align both of these perspectives and provide the best value in the long run.
If GPL/LGPL isn't sufficient for you, we'll be offering a commercial license with fair terms as an alternative.
