Iphone ios 18.1 update and Philips Respironics Dreammapper

Probably best to contact Philips directly. I'm trying to remember what I did when I got my replacement. I think I removed the previous device from the app. Went to Bluetooth Settings on my iPhone and had it forget the previous device. Then I Force Restarted my iPhone and started the pairing process anew. Another thing is if I remember correctly, the Bluetooth Pairing happens inside the App first. You will of course have to connect to your Wifi network on the device itself as well.

You have first paired it to your iPhone via Bluetooth? That's literally, the first thing you need to do. Then go in the Dreammaper App and remove the previous machine, then connect the new machine. You may need to call Philips, who can walk you through this if what I've suggested doesn't help. But I too got a replacement CPAP and his is what I had to do.