The "or later" bit was meaningless until the first GPLv3 (or later) code change was introduced, and it wasn't forced by anyone since it wasn't even part of the

The "or later" bit was meaningless until the first GPLv3 (or later) code change was introduced, and it wasn't forced by anyone since it wasn't even part of the license. Users of GPLv2-or-later software cannot use GPLv3 clauses against other users (such as patent grants), as either party can always claim to be using the code under either license. GPLv2-or-later is thus fine. The "unsuspecting part" comes from people relicensing under v3 without understanding how radioactive it is. And it is radioactive not because of any software-related concerns, but because of extraneous stuff (like Linus says). Funny enough, the most radioactive bits come from trying to cover things that are better fought in other grounds, like software patents.