This project has a dependency on the ArcGIS Runtime SDK for iOS 100.12.0 or greater (previous versions of 100.x will not work without modification to the build instructions, and version 10.2.5 will definitely not work).
The ArcGIS Runtime SDK is automatically added to the project as a dependency with the Swift Package Manager. An internet connection is required if the building on a new machine that has not yet downloaded the dependency.
The project is set to use the most recent minor version i.e. 100.12.0+, but not 100.13.0+. This is because Esri deprecates features in the minor releases. To use a more recent version of the ArcGIS Runtime SDK, set the version number in the package dependencies tab of the project build instructions.