Hi, I'm going to attempt to replace these Firex smoke detectors myself. can I just buy the most recent model of these and swap them out, leaving all the old wires? Or
Kidde Firex KF20 Mains Optical Smoke Alarm
Kidde KF30R Firex Mains Heat Alarm Rechargeable
FireX Smoke Alarm #4003 Low Traffic Area - New In Package | eBay