LGPL and MPL compatibility question

Matthew Flaschen matthew.flaschen at gatech.edu
Fri Apr 11 08:52:17 UTC 2008

Philippe Verdy wrote:
> Hugo Palma [mailto:hugo.m.palma at gmail.com] wrote:
>> I know GPL and MPL are incompatible. But i'm just not sure if 
>> that also means that LGPL and MPL are incompatible also.
> If the GPL and MPL are incompatible, then the MPL is also incompatible with
> the LGPL (because LGPL requires the compatibility with the GPL, as this is a
> right granted by the LGPL to change it at any time to GPL, so that LGPL
> libraries can be linked with GPL programs).

That says nothing about whether they're compatible, while the code is 
still under LGPL.  In my opinion, they probably are, because the MPL 
code "contains no derivative of any portion of the
Library [LGPL code]".  That means the MPL code is a "work that uses the 
Library", as defined in the LGPL.

Thus, the combination would seem acceptable because both MPL and LGPL 
"permit modification of the work for the customer's own use and reverse
engineering for debugging such modifications."

Again, IANAL and this is not legal advice.  Consult a lawyer about your 
precise situation.

Matt Flaschen

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