Looks like there are problems in Apple iOS land. The release iOS 8.0.1 to fix bugs in 8.0, and 8.0.1 was pulled when it caused major problems like these:
reports began flooding in that iOS 8.0.1 was breaking cellular reception and other features like Touch ID. Apple eventually removed the faulty update, but not before an untold number of users were able to install it. http://www.theverge.com/2014/9/24/6839235/apple-ios-8-0-1-released
Yes, it did say “breaking cellular reception”. And one of the main reasons I have a cell phone is cellular reception, i.e. making and receiving phone calls.
I was thinking of updating my phone today, thankfully I saw this article before I did so. Maybe I’ll update some time in October when Apple gets it right.