No, you're right. Here's the best "article" I can find about this at the moment: https://opensource.stackexchange.com/questions/7387/what-is-the-difference-be

No, you're right. Here's the best "article" I can find about this at the moment: https://opensource.stackexchange.com/questions/7387/what-is-the-difference-between-lgplv2-1-and-lgplv3 https://opensource.stackexchange.com/questions/7387/what-is-... (copy paste from a dead link.) Apple has the same problem as unity. Try this on a mac: % bash --version GNU bash, version 3.2.57... Copyright (C) 2007 Free Software Foundation, Inc. They can't upgrade bash past 3.2 (which is the last GPLv.2 release), so they're maintaining an ancient version themselves (it's old enough to smoke + vote + go to war in the US!), and they're trying to get users to switch to zsh. I looked at the LGPL 2.1, and the "or later" bit of the license is weird. Users can convert it to any version of GPL >= 2.1 at their discretion. However, the author of the library needs to specify LGPL (= any version), LGPL 2.1 (= exactly 2.1), or (recommended) "LGPL 2.1 or later" in a COPYING file. Unity says they "deprecated" LGPL code. That makes sense unless the code pins the LGPL version. Upstream LGPL vendors could rug-pull them, bash-style, at any moment. However, VLC's libraries are listed as "LGPL 2.1 only" here, so they explicitly claim they cannot rug pull (unless they jump to GPL3 -- that wouldn't be too surprising, since most of their stuff is AGPL, though it'd probably cause a fork): https://code.videolan.org/explore/projects/starred https://code.videolan.org/explore/projects/starred Except VLC didn't incorporate the license properly (COPYING and COPYING.lib don't say if they pin LGPL versions), and their README.md says: > libVLC, the engine is released under the LGPLv2 (or later) license. This allows embedding the engine in 3rd party applications, while letting them to be licensed under other licenses. https://code.videolan.org/videolan/vlc https://code.videolan.org/videolan/vlc So, Unity's probably right to be worried. "or later" includes v3, which is specifically incompatible with stuff like anti-cheat technology and consoles. However, my best guess is that Unity's worried about pissing off third parties that have patents on the algorithms VLC implements, and they use the LGPL thing as an excuse to avoid revealing the details of those private deals.