Good and bad licence changes

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Like most pages on LibrePlanet, this page is not written by FSF. This page carries an explicit notice because the topic sometimes attracts media attention and people unfamiliar with LibrePlanet might arrive at this page without knowing the (non-)relation to FSF.

Changing from a copyleft licence (e.g. GPL) to a weak copyleft (e.g. LGPL) or to a permissive licence (e.g. Apache License) is almost never a good idea.

The rare situations where it's a good idea

Using a weak copyleft or a permissive licence can be a good idea if:

  1. the functionality of the software is already widely available in proprietary software; AND
  2. wide adoption will help break a form of control that proprietary software companies have on a domain (i.e. via a format or protocol); AND
  3. the copyleft provisions are reducing adoption

Examples

Ogg Vorbis and Theora

The Ogg media suite is an example of when it's good to use a permissive licence.

VLC

A seemingly bad change:

QT toolkit

Bradley Kuhn says QT's GPL -> LGPL switch was a good move: LGPL'ing of Qt Will Encourage More Software Freedom

status.net and pump.io

status.net was AGPL, but the developers next genetion replacement was Apache Licence. The lead developer, Evan Prodromou says the change is because the software fits the three criteria mentioned above.

LibreOffice

LibreOffice (LO) was originally LGPLv3+ but has switched to MPL2. More precisely, it will be dual-licensed under both, but distributors can only be held to the weaker of the two sets of requirements, which is MPL2.

Is this justified? Maybe.

Most of the functionality in LO is also available in Apache Open Office (AOO), and AOO has a permissive licence (Apache License v2). This puts LO in a weak position because if they ask third-party projects to abide by the weak copyleft requirements of the LGPL, they might simply walk away and work with AOO instead.

glibc

"there are plenty of other C libraries; using the GPL for ours would have driven proprietary software developers to use another" as explained in Why you shouldn't use the Lesser GPL for your next library.

GCC runtime libraries

An example of crafting narrow GPL exceptions to address particular use cases rather than moving to a weaker copyleft or permissive license wholesale; in depth explanations by Bradley Kuhn and in the GCC runtime exception FAQ and rationale.

External links

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