MMRemote4 can remote control MediaMonkey 4, while MMRemote5 can remote control the newer MediaMonkey 5. Because of the huge changes from MediaMonkey 4 to MediaMonkey 5, the new version of the remote had to be almost completely rewritten. The user interfaces for MMRemote4 and MMRemote5 are almost identical, but the insides — especially all the parts that communicate with MediaMonkey — are very different.