Here’s another GPL’d game ported to the iPhone, like World Challenge that we mentioned earlier — XPilot, an old school multiplayer game that now has a new lease on life. But, as we pontificated in the World Challenge notes, there are those who have issues with this kind of resurrection; and in this case, it includes one of the original developers. From the Slashdot article “The Ethics of Selling GPLed Software For the iPhone”:

…We priced it at $2.99 on the App store (we don’t expect it to become the Next Big Thing, but hoped to recoup our costs — such as server charges and Apple’s annual $99 developer fee), released the source on our web page, then enthusiastically tracked down every member of the original community we could find to let them know of the hoped-for renaissance. Which is where things got muddy. After it hit the App store, one of the original developers of XPilot told us he feels adamantly that we’re betraying the spirit of the GPL by charging for it.

This would be the kind of person that Fake Steve Jobs coined the term ‘freetard’ for. The GPL not only doesn’t mandate a price of nothing, it explicitly allows the charging of whatever fee you see fit for distribution, so long as all source is made available. So nobody serious believes that said original developer has any point. But it does bring up where the real debatable point is, since you can’t recompile on your own phone or redistribute through the App Store without the $99/yr licensing fee by Apple, does that constitute a violation? If you read through the 581 and counting comments, you’ll see every shade of opinion … including a link to the one that we can take as authoritative, I have no doubt: Brett Smith. And who is Brett Smith, you ask? Why, he’s the “Licensing Compliance Officer” for the FSF. Seems that this subject was brough up last year with him over at Linux.com, and here’s the scoop: There is no barrier the FSF sees to GPLv2 compliance. However, GPLv3 is off the table:

…The iPhone Developer Program establishes Apple as the sole provider of iPhone applications. You can choose not to charge for an app you author, but the iTunes Store is the only channel through which it can be delivered to end users and installed. Apple signs the apps it approves with a cryptographic key. Unsigned apps won’t run on the iPhone.

This condition conflicts with section 6 of the GPLv3, the so-called “anti-TiVoization” provision. In particular, it prohibits Apple from distributing a GPLv3-licensed iPhone application without supplying the signing keys necessary to make modified versions of the application run, too.

Thus, you as the developer could attempt to place your code under the GPLv3, but Apple could not distribute it — and since only Apple-signed programs will run, no one else could distribute it either.

The FSF’s Smith says the fact that the author of the program (i.e., you) and the distributor of the binary (i.e., Apple) are unrelated entities makes no difference. “If a program is meant to be installed on a particular User Product, GPLv3 imposes the same requirements about providing Installation Information whether the software is directly installed on the device or conveyed separately.”

Because of the GPL’s viral nature, any app that is derived from other GPLv3 code must be licensed in a way that preserves GPLv3′s code signing requirement. But there are still projects that have chosen to retain earlier licenses, such as GPLv2, and prior versions of the GPL did not include the code signing requirement. Thus you could in theory place your work under GPLv2, as long as it was either entirely original or derived only from code licensed under GPLv2 and earlier…

So there you go, we’ve got that question officially settled then; any program licensed under GPLv2 is cool with the FSF for the App Store, long as you make the source available. Excellent. Soon as we find some free time under the couch or something we will definitely look at picking a project like these to port to the iPhone for the benefit of those who enjoy rooting through code written by their potential contract trolls.

In the meantime, support these fellows’ trailblazing efforts, pick up what all the fuss is about for a mere $1.99!