* Ivan Ristic:
The problem is that an Apache installation typically consists of many
modules, each with a potentially different licence. I am only aware of
the incompatibility between the GPLv2 and the ASL, although other
issues may exist. Although GPLv2 is our licence of choice, we do not
have an intention to force this licence upon other users and developers.
Do you need compatibility with pre-2.0 Apache licenses? The GPL version
3 is rumored to be compatible with the Apache License 2.0, so if you
switch to "GPL v2 or later", this might be sufficient.