Note that using the latest Xcode does not prevent your application from targeting older iOS versions. Apple requires using the most recent Xcode when submitting applications. Microsoft strongly recommends using the latest Xcode and most recent Xamarin.iOS release when developing and submitting applications. Bitcode builds (for tvOS and watchOS) can fail submission to the App Store unless an Xcode 9.0+ toolchain is used.In most cases enabling the managed linker will help (by removing the API). The static registrar requires Xcode headers files to build applications, leading to MT0091 or MT4109 errors if APIs are missing.Also some limitations might require workarounds, e.g.:
Using an older Xcode version (than the one mentioned in the above requirements) is often possible, but some features may not be available.