All the gnucash source code used in gpe-cash is "GPLv2 or later". The Gtk frontend for gpe-cash is GPLv3 or later. I am therefore using my option to distribute and modify the gnucash source code under a later version of the GPL, bringing the entire source code for gpe-cash under version 3 of the GPL. This specifically includes the shared library libqofcashobjects. Neil Williams <codehelp@debian.org>
You are NOT "bringing the entire source code for gpe-cash under version 3 of the GPL". If it was licenced "2 or later", it STAYS "2 or later".
What you are doing is saying "gpe-cash contains some code that is '2 or later' and some code that is '3 only' or '3 or later', therefore 3 is the only licence that is valid for gpe-cash".
To re-iterate. You are NOT changing the pre-existing licence on code you've borrowed. But because of the mix of licences, the only licence that is valid for the combined work is v3.
Cheers, Wol -- Anthony W. Youngman - anthony@thewolery.demon.co.uk