I want to fork a piece of code licensed under the Academic Free License. For the project, it would be preferable to re-license it under the ISC License or the 2-Clause BSD license, which are equivalent.

I understand that the AFL grants me things such as limitation of liability, but licensing consistency is much more important to the project, especially since we're talking about just 800 lines of code, a quarter of which I've modified in some way.

And it's very important for me to give these changes back to the community, given the fact that this is software relevant to security - I need the public scrutiny that I'll get by creating a public fork.

In short:

At the top of the file I want to say this, or something like it:

# Licensed under the Academic Free License, version 3
# Copyright (C) 2009 Original Author

# Licensed under the ISC License
# Copyright (C) 2012 Stefano Palazzo
# Copyright (C) 2012 Company

Am I allowed to do this?

My research so far indicates that it's not clear whether the AFL is GPL-Compatible, and I can't really understand any of the stuff concerning re-licensing to other permissive licenses. As a stop gap, I would also be okay with re-licensing under the GPL, however: I can find no consensus (though I can find disagreement) on whether this is allowed at all, and I don't want to risk it, of course.

• Wikipedia: ISC License
• Wikipedia: Academic Free License