This is an extremely niche issue but I just landed in Japan, unable to connect to any network. I called T-Mobile using Wifi calling through the airport's wifi network and they had me send over diagnostics. Well they informed me that my latest iOS check was failing and that was the cause for me not being able to roam internationally on an iPhone 6. Has anyone else ever noticed this issue? If not, I suppose this is a PSA for those on a beta OS looking to travel abroad.