The catch is, if a clone uses any 1.5 or later code, they have no choice but to release all their code under GPL v2. No exceptions, they can't even release a testnet only closed source release, or delay releasing the source a few weeks or months after the binary release. Clones also cannot license their code to other businesses under a license different than the GPL. We can, because we own the copyright. Clones cannot provide a white label blockchain to an interested business under a license different than the GPL. We can. No one can build a product that is considered a derivative work (i.e., is derived from the server side java code rather than just calling it over the network) on top of a clone blockchain and release it under a license different than the GPL, even if the clone developers are willing to license their code to that third party, because the clone code is based on ours, and including ours requires GPL. But a business can build a derivative work on top of our code under a different license, as long as it obtains the permission of the Nxt developers to do so under such custom license.
