To my surprise, I noticed that my iPhone 8 Plus running 11.0.2 drops from LTE to 3G whenever I start a call regardless if it's outbound or inbound. I was kind of miffed because it was working fine on my iPhone 6 running 10.3.3 and probably still is but I no longer have it in my possession. I called my carried but I didn't expect their call centre to be aware let alone know what VoLTE was and that's exactly what happened. I'm sure their engineers know by now though. I eventually discovered an article describing the issue to customers on the same carrier as I'm on (Fido) and it isn't just effecting iPhone 8/8 Plus users but any device updated to iOS 11. This is replicated on 11.0, 11.0.1 and 11.0.2. http://www.iphoneincanada.ca/carriers/rogers/fido-volte-ios-11/ I later contacted a friend who has an iPhone 8 who's also on the same carrier and he confirmed LTE is dropping to 3G during calls. I'm not sure whether it's iOS related or a carrier update required to play friendly with iOS 11. I initially thought maybe my carrier hadn't yet added the iPhone 8 to their VoLTE supported devices list if that's even a thing but it doesn't seem to be the cause. To clarify: 1. All iPhones since probably the 5S support VoLTE 2. My carrier currently supports VoLTE and has so since 2015 3. I don't believe it's a hardware related matter since other iOS 11 users are noticing the same behavior after updating regardless of what model iPhone they have 4. Prior to iOS 11 all VoLTE enabled iPhones we're enjoying VoTLE including mines 5. I haven't changed carriers I'm writing this post to inform effected users and to ask the community if they have some insight on how this whole thing works. Do carriers normally enable the feature on a phone by phones bases, will Apple have to fix this in a future iOS update or does the carrier simply have to push down a new carrier update. Thanks!