Hi. I have testet a lot around this issue now and finally got it to work. Here is what I’ve tested: IOS 11.3, 11.4 and 12 NOGO with new screen. Switched back to the old screen, was able to pair. Updated watch to 5.0.1 . switch screen and still OK. Factory reset on the watch and still able to Pair. So to all: Upgrade watch before switching screen!