// swift-tools-version:5.0
import PackageDescription

let package = Package(
    name: "TinyConstraints",
    platforms: [
        .macOS(.v10_11), .iOS(.v9), .tvOS(.v9)
    ],
    products: [
        .library(name: "TinyConstraints", targets: ["TinyConstraints"])
    ],
    targets: [
        .target(
            name: "TinyConstraints",
            path: "TinyConstraints"
        )
    ],
    swiftLanguageVersions: [.v5]
)

// swift-tools-version:4.2
import PackageDescription

let package = Package(
    name: "TinyConstraints",
    products: [
        .library(name: "TinyConstraints", targets: ["TinyConstraints"])
    ],
    targets: [
        .target(
            name: "TinyConstraints",
            path: "TinyConstraints"
        )
    ]
)

--- 
+++ 
@@ -1,8 +1,11 @@
-// swift-tools-version:4.2
+// swift-tools-version:5.0
 import PackageDescription
 
 let package = Package(
     name: "TinyConstraints",
+    platforms: [
+        .macOS(.v10_11), .iOS(.v9), .tvOS(.v9)
+    ],
     products: [
         .library(name: "TinyConstraints", targets: ["TinyConstraints"])
     ],
@@ -11,5 +14,6 @@
             name: "TinyConstraints",
             path: "TinyConstraints"
         )
-    ]
+    ],
+    swiftLanguageVersions: [.v5]
 )
Add platform requirements, and bump the required tools version to Swift 5.0
