Question about the old BSD license and GPL (gtkipmsg)

[Junichi Uekawa <dancer@netfort.gr.jp>]

Hello,


I have been looking at gtkipmsg, which is a patched version of 
xipmsg, which is a patched version of Windows version of IP Messenger.

Now, IP Messenger (the original program) was released under 
the old BSD license, and xipmsg follows that. The latest version 
of IP Messenger is released under the newer BSD license.

gtkipmsg is a derivative version of xipmsg, and it claims that
it is distributed under the terms of GPL2.

I see that at www.gnu.org, the old BSD license is not compatible with 
GPL, but I cannot understand why.

I do not really understand the reasoning behind it being non-compatible,
and I am not really sure gtkipmsg would be 
qualified as DFSG-free.

Thanks,
	junichi



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