first the spektrum module is only dsm and will not work with dsm2 recievers . yes hk has only dsm2 recievers . obviously these are knock offs but still work . spektrum only had dsm technology at the release of the m8/m11. there is nothing that is forward compatable . the new spektrum radios however are backwards compatable . the new dx4s is a dsmr radio that is compatable with any spektrum reciever.