Comment 1 for bug 1270374

Dulwich is under the GPL version 2 *or later*. You can use it under the terms of the GPLv3, which is compatible with the Apache v2 license.

I did look into changing the license of Dulwich to the Apachev2 license a while ago, but this effort has stalled because I haven't heard back from all contributors yet. See https://lists.launchpad.net/dulwich-users/msg00758.html