title: UINavigationBar back button not showing on iPhone X iOS 11
body: <p>I am facing an issue, When i run my app on iPhone SE simulator it shows back button on nav bar like this.</p>
  
  <p><a href="https://i.stack.imgur.com/0nu0r.png" rel="noreferrer"><img src="https://i.stack.imgur.com/0nu0r.png" alt="enter image description here"></a></p>
  
  <p>But when i run the same app on iPhone X, iPhone 8 and iPhone 8 plus iOS 11 and XCode 9 there is no back button on nav bar and its for all ViewControllers not for specific viewController. Here is the example</p>
  
  <p><a href="https://i.stack.imgur.com/4HEFO.png" rel="noreferrer"><img src="https://i.stack.imgur.com/4HEFO.png" alt="enter image description here"></a></p>
  
  <p>Can anyone tell why is this happening.</p>