diff --git a/Bounded Priority Queue/BoundedPriorityQueue.playground/Contents.swift b/Bounded Priority Queue/BoundedPriorityQueue.playground/Contents.swift
index f8e219c13..d6204abec 100644
--- a/Bounded Priority Queue/BoundedPriorityQueue.playground/Contents.swift	
+++ b/Bounded Priority Queue/BoundedPriorityQueue.playground/Contents.swift	
@@ -1,8 +1,3 @@
-// last checked with Xcode 9.0b4
-#if swift(>=4.0)
-print("Hello, Swift 4!")
-#endif
-
 struct Message: Comparable, CustomStringConvertible {
   let name: String
   let priority: Int
diff --git a/Bounded Priority Queue/BoundedPriorityQueue.playground/contents.xcplayground b/Bounded Priority Queue/BoundedPriorityQueue.playground/contents.xcplayground
index 06828af92..69d154d1e 100644
--- a/Bounded Priority Queue/BoundedPriorityQueue.playground/contents.xcplayground	
+++ b/Bounded Priority Queue/BoundedPriorityQueue.playground/contents.xcplayground	
@@ -1,4 +1,4 @@
 <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
-<playground version='5.0' target-platform='osx'>
+<playground version='5.0' target-platform='osx' last-migration='1000'>
     <timeline fileName='timeline.xctimeline'/>
 </playground>
\ No newline at end of file
diff --git a/Bounded Priority Queue/BoundedPriorityQueue.playground/playground.xcworkspace/xcshareddata/IDEWorkspaceChecks.plist b/Bounded Priority Queue/BoundedPriorityQueue.playground/playground.xcworkspace/xcshareddata/IDEWorkspaceChecks.plist
new file mode 100644
index 000000000..18d981003
--- /dev/null
+++ b/Bounded Priority Queue/BoundedPriorityQueue.playground/playground.xcworkspace/xcshareddata/IDEWorkspaceChecks.plist	
@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>IDEDidComputeMac32BitWarning</key>
+	<true/>
+</dict>
+</plist>
diff --git a/Bounded Priority Queue/Tests/Tests.xcodeproj/project.pbxproj b/Bounded Priority Queue/Tests/Tests.xcodeproj/project.pbxproj
index 842c51695..11f907b47 100644
--- a/Bounded Priority Queue/Tests/Tests.xcodeproj/project.pbxproj	
+++ b/Bounded Priority Queue/Tests/Tests.xcodeproj/project.pbxproj	
@@ -86,7 +86,7 @@
 				TargetAttributes = {
 					B80004B21C83E342001FE2D7 = {
 						CreatedOnToolsVersion = 7.2.1;
-						LastSwiftMigration = 0820;
+						LastSwiftMigration = 1000;
 					};
 				};
 			};
@@ -226,7 +226,7 @@
 				SDKROOT = macosx;
 				SWIFT_OBJC_BRIDGING_HEADER = "";
 				SWIFT_OPTIMIZATION_LEVEL = "-Onone";
-				SWIFT_VERSION = 3.0;
+				SWIFT_VERSION = 4.2;
 			};
 			name = Debug;
 		};
@@ -269,7 +269,7 @@
 				PRODUCT_NAME = "$(TARGET_NAME)";
 				SDKROOT = macosx;
 				SWIFT_OBJC_BRIDGING_HEADER = "";
-				SWIFT_VERSION = 3.0;
+				SWIFT_VERSION = 4.2;
 			};
 			name = Release;
 		};
diff --git a/Bounded Priority Queue/Tests/Tests.xcodeproj/project.xcworkspace/xcshareddata/IDEWorkspaceChecks.plist b/Bounded Priority Queue/Tests/Tests.xcodeproj/project.xcworkspace/xcshareddata/IDEWorkspaceChecks.plist
new file mode 100644
index 000000000..18d981003
--- /dev/null
+++ b/Bounded Priority Queue/Tests/Tests.xcodeproj/project.xcworkspace/xcshareddata/IDEWorkspaceChecks.plist	
@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>IDEDidComputeMac32BitWarning</key>
+	<true/>
+</dict>
+</plist>