RealNetworks is doubly concerned that Apple will not only continue to break Harmony’s interoperability with iPods but may even resolve to sue Real. Harmony allows users to play songs from Real’s Rhapsody digital music service on Apple’s iPods and was launched in July 2004 and has been tweaked to work with each generation of iPods only to have Apple shut the door each time. It represents the only chink of light through a seemingly solid wall of non-interoperability between Apple-backed services and Microsoft/Windows Media-backed services.