Re: copyright assignment?
More info on dual licensing which- as the post above notes- is used by many commercially-supported open source projects.
Whether one considers it good or bad, it's definitely an issue to be considered if you're contributing to a project and the entity controlling it wants- or rather, requires- your copyright to be assigned in order to be accepted.
Essentially, it's just using the fact that they own the copyright to offer the code under different terms than the GPL. (This could be done in theory without copyright assignment, but would require every contributor to agree to license their work under the new terms, which is often impractical).
This doesn't negate the freedom to distribute the last GPLed version, nor to fork it (but only as GPL unless the company agrees to license the parts they own the rights to under different terms, something they'd be unlikely to do here).
Because they own the rights, they're free not to require themselves(!) to adhere to the conditions they offered it to others under, i.e. to not be forced to distribute the newer versions as GPL.
It should be made clear that this is perfectly legal, but only if the contributors agree to assign their copyright to another entity (and that entity hence owns the copyright in its entirety). Or if they wrote it entirely themselves.
Of course, the work wasn't originally *theirs*, and this is arguably the problem with copyright assignment and with projects that *require* copyright assignment. But that's up to contributors to decide...