We need to upgrade an existing (and simple) App developed a couple of years ago. It was running fine up to the moment Apple migrate Swift 2 to Swift 3, and later to Swift 4. So we need to create the App again from scratch but reusing as much code as possible.
1- It is a functional app that just have 4-5 views (12 controllers and 8 models, that are 100 source code lines each as average)
2- It exists lot of source code that do not need to be migrated, as it was part of testing, so you can feel free to delete all source code that it is not used just to avoid converting unused code.
3- Most part of the App is developed using third party code that is already available as Swift 4 code; either in github or as an updated CocoaPod:
For instance a couple of libraries used are: [login to view URL] or PXGoogleDirections available as a CocoaPod that are already available for Swift 4.
We need to publish the App in the Apple TestFlight as it is not already published as a real App in the App store.