I work for the city of Blue Ash and have not heard that for the Hamilton County system at all. If they did that the cost would be enormous as in Blue Ash we have around 50 radios (police dept only, unsure of fire and other) that would have to be reprogrammed. We don't have any of the old radios to fall back on at all.
Performance of the system though has really gotten terrible lately though. There is just a massive amount of digital breakup and the dead spots seem to be increasing. Not sure why this is though.