Series 3 iwatch wont pair with iPhone 5S
I bought an iwatch series 3 last year. It paired with my iPhone 5S no probs. I accidentally smashed the watch and got a new one last month. Now the new one wont pair with my 5S. Some posts say you can pair with a 5S, as I did, but others say I need at least a 6.
What has changed please and how do i pair with the 5S?
Apple Watch Series 3, iOS 11.3.1