I have removed all of my V1 Iris contact sensors and use the V2 version now. Reason is/was simple, the V1 devices don’t join through a repeater as they use the special V1 Iris protocol. It’s not as bad during the initial install when you can join them close to the hub. But once installed and you need to rejoin (for whatever reason) it is is a PIA. The V2 use standard Zigbee and can join through a repeater in place.