diff --git a/Array2D/Array2D.playground/Contents.swift b/Array2D/Array2D.playground/Contents.swift
index 77c0b364c..d31d77540 100644
--- a/Array2D/Array2D.playground/Contents.swift
+++ b/Array2D/Array2D.playground/Contents.swift
@@ -1,8 +1,3 @@
-// last checked with Xcode 9.0b4
-#if swift(>=4.0)
-print("Hello, Swift 4!")
-#endif
-
 /*
  Two-dimensional array with a fixed number of rows and columns.
  This is mostly handy for games that are played on a grid, such as chess.
diff --git a/Array2D/Tests/Tests.xcodeproj/project.pbxproj b/Array2D/Tests/Tests.xcodeproj/project.pbxproj
index a0fb1480b..af9b7c3b8 100644
--- a/Array2D/Tests/Tests.xcodeproj/project.pbxproj
+++ b/Array2D/Tests/Tests.xcodeproj/project.pbxproj
@@ -226,7 +226,7 @@
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/../Frameworks @loader_path/../Frameworks";
 				PRODUCT_BUNDLE_IDENTIFIER = swift.algorithm.club.Tests;
 				PRODUCT_NAME = "$(TARGET_NAME)";
-				SWIFT_VERSION = 3.0;
+				SWIFT_VERSION = 4.2;
 			};
 			name = Debug;
 		};
@@ -238,7 +238,7 @@
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/../Frameworks @loader_path/../Frameworks";
 				PRODUCT_BUNDLE_IDENTIFIER = swift.algorithm.club.Tests;
 				PRODUCT_NAME = "$(TARGET_NAME)";
-				SWIFT_VERSION = 3.0;
+				SWIFT_VERSION = 4.2;
 			};
 			name = Release;
 		};