       .target(name: "RxTest", dependencies: ["RxSwift"]),
     ],
     Target.allTests()
-  ] as [[Target]]).flatMap { $0 }
+  ] as [[Target]]).flatMap { $0 },
+  swiftLanguageVersions: [.v5]
 )

// swift-tools-version:4.2

import PackageDescription



let package = Package(
  name: "RxSwift",
  platforms: [
    .macOS(.v10_10), .iOS(.v8), .tvOS(.v9), .watchOS(.v3)
  ],
  products: ([
    [
      .library(name: "RxSwift", targets: ["RxSwift"]),
