The new check called ModuleDirectoryLayout helps ensure that the modules of a project follow a configurable directory layout. One such layout is the Maven Standard Directory Layout, but you can define your own! Also, there are some minor improvements to the RegexpOnString check and minor fixes.
This is a new major version because the dependency structure has changed. We now depend on some external libraries
other than Checkstyle. IntelliJ and command line users will have to use the new -all artifact which includes the
external libraries so that nothing else needs to be downloaded.