diff --git a/Package.swift b/Package.swift
index ae16f6fe..eca6e105 100644
--- a/Package.swift
+++ b/Package.swift
@@ -4,6 +4,12 @@ import PackageDescription
 
 let package = Package(
   name: "NearbyConnections",
+  platforms: [
+    .iOS(.v11),
+    .macOS(.v10_13),
+    .tvOS(.v11),
+    .watchOS(.v4),
+  ],
   products: [
     // Products define the executables and libraries a package produces, and make them visible to other packages.
     .library(