I have updated 2 iPhones and a iPad to 14.8 which includes the patch from Apple to stop the zero click malware. I am also using an older iMac running High Sierra 10.13.6. I am not getting updates from Mac for this now of course. Messages still sync with it though from my other devices. As I only use Messages on my iPhones I don't have much use for Messages on the iMac and was wondering if I can remove it from the iMac and if so what would be the correct way to do it.