Whipped up some demo code for a proof of concept I needed. Used FPDM which states as its license "FPDF". The FPDF license seems Free to me -

Permission is hereby granted, free of charge, to any person obtaining a copy of this software to use, copy, modify, distribute, sublicense, and/or sell copies of the software, and to permit persons to whom the software is furnished to do so.


I needed to fix a few things in FPDM. Can I distribute my code, and the changed version of FPDM under the GPLv2 ?

If no, can I distribute the fixed version of FPDM under the same "FPDF license" I obtained it under, and my own original code that calls it as GPLv2 ?

If no to all of this, what license can I use that ensures anyone else with a copy of my work is able to use it permissively? I prefer the GPLv2 for reasons... and the code is PHP, so it is "open" if not Free.

1 Answer 1


The FPDF license is a permissive license very similar to the MIT license. The permissive nature of the license allows you to distribute both your code and the modified FPDM library under the GPLv2 license.

However, if your changes to the FPDM library could be of interest to the maintainers of the original library, then it would make thing a lot easier if you distribute the changed FDPM library under the FPDF license (same as the original). The rest of your project can still be licensed under the GPLv2 license.
Then your change can be incorporated 'upstream' without the difficulties that come with the code having a different license.

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