Sorry for late bringing up this topic, for whose do not know, Tom answered on Solomon question about new CUPS licensing in:
https://lists.fedoraproject.org/archives/list/legal@lists.fedoraproject.org/...
To sum it up (from what I understood):
Projects under GPLv2+ are compatible, LGPL, LGPLv2 and LGPLv3 too. In case of GPLv2 only upstream opinion matters and Mike as upstream said CUPS falls under "OS-supplied library", so SWs, which have CUPS dynamically linked, are license compatible.
So project under GPLv2+ and compatible are okay, GPLv2 only should change license or add into license file sentence mentioning about that's okay to link against CUPS, because it is OS-supplied library.