What should the new license text include when forking a project?

Question

When forking a project, what is the responsibility of the new project as regards the license text? Specifically, the BSD license (a permissive one), includes the text:

Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.

So if I'm making a new version of the same project, would I need to continue to include the old notification file? Would it be sufficient to simply append the new copyright to the old one, like this?

Copyright (c) 1999-2006 [Old Project], 2009 [New Project]

If I was switching licenses (say, to a GPL), would I still need to include the old license text?

Answer 1

First, you can't switch licenses. You can release modern BSD-licensed code under the GPL, or for that matter a proprietary license, but that doesn't free you from any limits of the BSD license. Both licenses will apply.

Therefore, you need to keep the copyright notice, the conditions, and the disclaimer. Make sure this doesn't conflict with whatever GPL version you're using, as they can get a bit sticky about passed-on requirements.