Im trying to build a Navigation Bar - descirbed here apple developer link - https://developer.apple.com/documentation/uikit/uinavigationcontroller but simple example is not working. I'm using xcode 12 and swift 5. I created Navigation Controller as entry point - Root View Controller with button inside which doing show Segue to next View Controller - on all tutorials and material on internet effect is that I see Back button in left corner. In my case its not visible but when I click in that place it's working. Is this any bug with xcode 12 ? What can I do wrong ?

I'm trying to implement SIP calls within VialerSIPLib - https://github.com/VoIPGRID/VialerSIPLib Im newbie in ios development. I have successfully run example project but I have an issue when trying to add library into my project. Installation instruction is saying that all we need to do is install lib with CocoaPods. For a testing I have created new project from the scratch and install/update pod  pod 'VialerSIPLib'  but still I'm unable to use library in AppDelegate. Cannot find 'CallKitProviderDelegate' in scope. How can I make AppDelegate to see pod dependencies ? I'm using xcode 12 and swift 5. Target os is 14.0 Any help appreciated. Thanks in advance