Earlier quoted context omitted.
If I take a GPLv2-or-later work, change the license notice to say GPLv2-only (or GPLv3-only, or GPLv3-or-later), and distribute it with that modified notice, have I violated the copyright licenses or copyright law? IANAL but I believe the answer is "No". Now, if all I've done is change the license notice, my change is legally ineffective – anyone who receives it from me can change it back to the original GPLv2-or-lat…
> IANAL but I believe the answer is "No". The answer is "Yes". Think about it this way: the license is "GPLv2 or later", not "GPLv2" or "GPLv3". If you change the license notice, you are changing the terms in which people will receive the code from you. The GPL (both of them) clearly says you cannot do this. You have to distribute modified works under the exact same terms you received the original work, or you lose t…
> Red Moon is licensed under the GNU General Public License version 3 or (at your option) any later version by the contributors.
As this reads to me, I am offering you a choice of licenses. You may use Red Moon under the GPLv3, or you may choose a later version of the GPL. Or, you could choose both, if you wish to distribute your derivative as GPLv3-or-later.
Put differently, a GPLv2-or-later currently means a dual-license, under both v2 and v3 (and an automatic relicensing to triple license if v4 is released, etc).