/build/Sources/App/routes.swift:31:23: error: 'URLSession' is unavailable: This type has moved to the FoundationNetworking module. Import that module to use it. let session = URLSession(configuration: .default) ^~~~~~~~~~ Foundation.URLSession:2:18: note: 'URLSession' has been explicitly marked unavailable here public typealias URLSession = AnyObject 確かにFoundationNetworkingに移ったって書いてありましたわ。