I ordered the firm ware up grade for the OMNI 6 and while on the phone asked for the IMD upgrade. The letter, dated 10/94, said that they didn't think that the IMD upgrade was necessary or would be noticeable for US hams. The parts and detailed instructions were included. I will make the changes, but I guess it is much ado about nothing....... Still a great outfit to deal with 73, Jim WB2TPS