Apple watch series 4 pair with iPhone 5s

From what I have read I should be able to pair an apple watch series 4 (GPS) to an iPhone 5s. When I attempt to pair it, the watch app says the phone needs to be updated but is is running the latest iOS 12.5. I have restarted the phone multiple times. I was half successful once but the app sat there for 20 minutes saying finishing pairing while thr watch looked like it wasn't paired.