GWT - Module.gwt.xml - XML validation warning
There's already a bug report here.
For now, you can still use the one from 2.5.1
<!DOCTYPE module PUBLIC "-//Google Inc.//DTD Google Web Toolkit 2.5.1//EN" "http://google-web-toolkit.googlecode.com/svn/tags/2.5.1/distro-source/core/src/gwt-module.dtd">UPDATE:
The new DTDs are now available here:
http://www.gwtproject.org/doctype/<version-number>/gwt-module.dtdSo for example:
http://www.gwtproject.org/doctype/2.8.0/gwt-module.dtd