The core Drools team will not have time to update the xml xsd's and
parser for the 5.0 release. The XML will continue to work, but you won't
be able to use any of the new features, and thus restricted to 4.0 level
features. If anyone from the community wants to take this on, then
please do, otherwise it'll have to wait until a later date after 5.0
when the core devs can work on this.
Mark