RDT 0.4.1 has been developed and tested for Eclipse M8. Thanks to quite a few bug reports we could fix several bugs particularly concerning the outline view and code formatter. For detailed information see the Changelog and the documentation at
RDT can be installed via zip file or using the update site at http://rubyeclipse.sf.net/updatesite. See home page for further informations. If you have 0.4.0 installed, using Help>Software Updates>Find and Install... should be the simplest way to update.