diff --git a/.swift-version b/.swift-version
index 9f55b2c..5186d07 100644
--- a/.swift-version
+++ b/.swift-version
@@ -1 +1 @@
-3.0
+4.0
diff --git a/Example/Example.xcodeproj/project.pbxproj b/Example/Example.xcodeproj/project.pbxproj
index 6539e2c..bc27ab2 100644
--- a/Example/Example.xcodeproj/project.pbxproj
+++ b/Example/Example.xcodeproj/project.pbxproj
@@ -188,18 +188,18 @@
 			attributes = {
 				LastSwiftMigration = 0710;
 				LastSwiftUpdateCheck = 0710;
-				LastUpgradeCheck = 0800;
+				LastUpgradeCheck = 0900;
 				ORGANIZATIONNAME = molabo;
 				TargetAttributes = {
 					FF828F141A74E52500DC12EF = {
 						CreatedOnToolsVersion = 6.1.1;
 						DevelopmentTeam = 8Y439RUF7P;
-						LastSwiftMigration = 0800;
+						LastSwiftMigration = 0900;
 					};
 					FF828F291A74E52500DC12EF = {
 						CreatedOnToolsVersion = 6.1.1;
 						DevelopmentTeam = 8Y439RUF7P;
-						LastSwiftMigration = 0800;
+						LastSwiftMigration = 0900;
 						ProvisioningStyle = Automatic;
 						TestTargetID = FF828F141A74E52500DC12EF;
 					};
@@ -307,14 +307,20 @@
 				CLANG_CXX_LIBRARY = "libc++";
 				CLANG_ENABLE_MODULES = YES;
 				CLANG_ENABLE_OBJC_ARC = YES;
+				CLANG_WARN_BLOCK_CAPTURE_AUTORELEASING = YES;
 				CLANG_WARN_BOOL_CONVERSION = YES;
+				CLANG_WARN_COMMA = YES;
 				CLANG_WARN_CONSTANT_CONVERSION = YES;
 				CLANG_WARN_DIRECT_OBJC_ISA_USAGE = YES_ERROR;
 				CLANG_WARN_EMPTY_BODY = YES;
 				CLANG_WARN_ENUM_CONVERSION = YES;
 				CLANG_WARN_INFINITE_RECURSION = YES;
 				CLANG_WARN_INT_CONVERSION = YES;
+				CLANG_WARN_NON_LITERAL_NULL_CONVERSION = YES;
+				CLANG_WARN_OBJC_LITERAL_CONVERSION = YES;
 				CLANG_WARN_OBJC_ROOT_CLASS = YES_ERROR;
+				CLANG_WARN_RANGE_LOOP_ANALYSIS = YES;
+				CLANG_WARN_STRICT_PROTOTYPES = YES;
 				CLANG_WARN_SUSPICIOUS_MOVE = YES;
 				CLANG_WARN_UNREACHABLE_CODE = YES;
 				CLANG_WARN__DUPLICATE_METHOD_MATCH = YES;
@@ -354,14 +360,20 @@
 				CLANG_CXX_LIBRARY = "libc++";
 				CLANG_ENABLE_MODULES = YES;
 				CLANG_ENABLE_OBJC_ARC = YES;
+				CLANG_WARN_BLOCK_CAPTURE_AUTORELEASING = YES;
 				CLANG_WARN_BOOL_CONVERSION = YES;
+				CLANG_WARN_COMMA = YES;
 				CLANG_WARN_CONSTANT_CONVERSION = YES;
 				CLANG_WARN_DIRECT_OBJC_ISA_USAGE = YES_ERROR;
 				CLANG_WARN_EMPTY_BODY = YES;
 				CLANG_WARN_ENUM_CONVERSION = YES;
 				CLANG_WARN_INFINITE_RECURSION = YES;
 				CLANG_WARN_INT_CONVERSION = YES;
+				CLANG_WARN_NON_LITERAL_NULL_CONVERSION = YES;
+				CLANG_WARN_OBJC_LITERAL_CONVERSION = YES;
 				CLANG_WARN_OBJC_ROOT_CLASS = YES_ERROR;
+				CLANG_WARN_RANGE_LOOP_ANALYSIS = YES;
+				CLANG_WARN_STRICT_PROTOTYPES = YES;
 				CLANG_WARN_SUSPICIOUS_MOVE = YES;
 				CLANG_WARN_UNREACHABLE_CODE = YES;
 				CLANG_WARN__DUPLICATE_METHOD_MATCH = YES;
@@ -400,7 +412,8 @@
 				PRODUCT_BUNDLE_IDENTIFIER = "com.molabo.$(PRODUCT_NAME:rfc1034identifier)";
 				PRODUCT_NAME = "$(TARGET_NAME)";
 				PROVISIONING_PROFILE = "";
-				SWIFT_VERSION = 3.0;
+				SWIFT_SWIFT3_OBJC_INFERENCE = On;
+				SWIFT_VERSION = 4.0;
 				TARGETED_DEVICE_FAMILY = "1,2";
 			};
 			name = Debug;
@@ -419,7 +432,8 @@
 				PRODUCT_BUNDLE_IDENTIFIER = "com.molabo.$(PRODUCT_NAME:rfc1034identifier)";
 				PRODUCT_NAME = "$(TARGET_NAME)";
 				PROVISIONING_PROFILE = "";
-				SWIFT_VERSION = 3.0;
+				SWIFT_SWIFT3_OBJC_INFERENCE = On;
+				SWIFT_VERSION = 4.0;
 				TARGETED_DEVICE_FAMILY = "1,2";
 			};
 			name = Release;
@@ -442,7 +456,8 @@
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks @loader_path/Frameworks";
 				PRODUCT_BUNDLE_IDENTIFIER = "com.molabo.$(PRODUCT_NAME:rfc1034identifier)";
 				PRODUCT_NAME = "$(TARGET_NAME)";
-				SWIFT_VERSION = 3.0;
+				SWIFT_SWIFT3_OBJC_INFERENCE = On;
+				SWIFT_VERSION = 4.0;
 				TEST_HOST = "$(BUILT_PRODUCTS_DIR)/Example.app/Example";
 			};
 			name = Debug;
@@ -461,7 +476,8 @@
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks @loader_path/Frameworks";
 				PRODUCT_BUNDLE_IDENTIFIER = "com.molabo.$(PRODUCT_NAME:rfc1034identifier)";
 				PRODUCT_NAME = "$(TARGET_NAME)";
-				SWIFT_VERSION = 3.0;
+				SWIFT_SWIFT3_OBJC_INFERENCE = On;
+				SWIFT_VERSION = 4.0;
 				TEST_HOST = "$(BUILT_PRODUCTS_DIR)/Example.app/Example";
 			};
 			name = Release;
diff --git a/Example/Example.xcodeproj/xcshareddata/xcschemes/Example.xcscheme b/Example/Example.xcodeproj/xcshareddata/xcschemes/Example.xcscheme
index 73f25ec..e57c5bf 100644
--- a/Example/Example.xcodeproj/xcshareddata/xcschemes/Example.xcscheme
+++ b/Example/Example.xcodeproj/xcshareddata/xcschemes/Example.xcscheme
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <Scheme
-   LastUpgradeVersion = "0800"
+   LastUpgradeVersion = "0900"
    version = "1.3">
    <BuildAction
       parallelizeBuildables = "YES"
@@ -40,6 +40,7 @@
       buildConfiguration = "Debug"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      language = ""
       shouldUseLaunchSchemeArgsEnv = "YES">
       <Testables>
          <TestableReference
@@ -69,6 +70,7 @@
       buildConfiguration = "Debug"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      language = ""
       launchStyle = "0"
       useCustomWorkingDirectory = "NO"
       ignoresPersistentStateOnLaunch = "NO"
diff --git a/Example/Example.xcodeproj/xcshareddata/xcschemes/ExampleTests.xcscheme b/Example/Example.xcodeproj/xcshareddata/xcschemes/ExampleTests.xcscheme
index b9535ef..e50f90a 100644
--- a/Example/Example.xcodeproj/xcshareddata/xcschemes/ExampleTests.xcscheme
+++ b/Example/Example.xcodeproj/xcshareddata/xcschemes/ExampleTests.xcscheme
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <Scheme
-   LastUpgradeVersion = "0800"
+   LastUpgradeVersion = "0900"
    version = "1.3">
    <BuildAction
       parallelizeBuildables = "YES"
@@ -26,6 +26,7 @@
       buildConfiguration = "Debug"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      language = ""
       shouldUseLaunchSchemeArgsEnv = "YES">
       <Testables>
          <TestableReference
@@ -55,6 +56,7 @@
       buildConfiguration = "Debug"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      language = ""
       launchStyle = "0"
       useCustomWorkingDirectory = "NO"
       ignoresPersistentStateOnLaunch = "NO"
diff --git a/Example/Example/DetailViewController.swift b/Example/Example/DetailViewController.swift
index e201f40..76a9a3f 100644
--- a/Example/Example/DetailViewController.swift
+++ b/Example/Example/DetailViewController.swift
@@ -41,7 +41,7 @@ class DetailViewController: UIViewController {
     //   it WAS `moved` at the time emmited.
     //   So use `getTouches` func for limited debug purpose.
     //   If you want to know the exact value, please override `handleEvent:` in UIWindow+Swizzle.swift.
-    func logTouches(timer: Timer) {
+    @objc func logTouches(timer: Timer) {
         for (idx, touch) in Visualizer.getTouches().enumerated() {
             print("[\(idx)] location: \(touch.location(in: self.view))")
         }
diff --git a/TouchVisualizer.xcodeproj/project.pbxproj b/TouchVisualizer.xcodeproj/project.pbxproj
index 7ac96dc..8264c78 100644
--- a/TouchVisualizer.xcodeproj/project.pbxproj
+++ b/TouchVisualizer.xcodeproj/project.pbxproj
@@ -112,12 +112,12 @@
 			attributes = {
 				LastSwiftMigration = 0710;
 				LastSwiftUpdateCheck = 0730;
-				LastUpgradeCheck = 0800;
+				LastUpgradeCheck = 0900;
 				ORGANIZATIONNAME = molabo;
 				TargetAttributes = {
 					FF1A1A9E1AFF6C2200267156 = {
 						CreatedOnToolsVersion = 6.4;
-						LastSwiftMigration = 0800;
+						LastSwiftMigration = 0900;
 					};
 				};
 			};
@@ -171,14 +171,20 @@
 				CLANG_CXX_LIBRARY = "libc++";
 				CLANG_ENABLE_MODULES = YES;
 				CLANG_ENABLE_OBJC_ARC = YES;
+				CLANG_WARN_BLOCK_CAPTURE_AUTORELEASING = YES;
 				CLANG_WARN_BOOL_CONVERSION = YES;
+				CLANG_WARN_COMMA = YES;
 				CLANG_WARN_CONSTANT_CONVERSION = YES;
 				CLANG_WARN_DIRECT_OBJC_ISA_USAGE = YES_ERROR;
 				CLANG_WARN_EMPTY_BODY = YES;
 				CLANG_WARN_ENUM_CONVERSION = YES;
 				CLANG_WARN_INFINITE_RECURSION = YES;
 				CLANG_WARN_INT_CONVERSION = YES;
+				CLANG_WARN_NON_LITERAL_NULL_CONVERSION = YES;
+				CLANG_WARN_OBJC_LITERAL_CONVERSION = YES;
 				CLANG_WARN_OBJC_ROOT_CLASS = YES_ERROR;
+				CLANG_WARN_RANGE_LOOP_ANALYSIS = YES;
+				CLANG_WARN_STRICT_PROTOTYPES = YES;
 				CLANG_WARN_SUSPICIOUS_MOVE = YES;
 				CLANG_WARN_UNREACHABLE_CODE = YES;
 				CLANG_WARN__DUPLICATE_METHOD_MATCH = YES;
@@ -222,14 +228,20 @@
 				CLANG_CXX_LIBRARY = "libc++";
 				CLANG_ENABLE_MODULES = YES;
 				CLANG_ENABLE_OBJC_ARC = YES;
+				CLANG_WARN_BLOCK_CAPTURE_AUTORELEASING = YES;
 				CLANG_WARN_BOOL_CONVERSION = YES;
+				CLANG_WARN_COMMA = YES;
 				CLANG_WARN_CONSTANT_CONVERSION = YES;
 				CLANG_WARN_DIRECT_OBJC_ISA_USAGE = YES_ERROR;
 				CLANG_WARN_EMPTY_BODY = YES;
 				CLANG_WARN_ENUM_CONVERSION = YES;
 				CLANG_WARN_INFINITE_RECURSION = YES;
 				CLANG_WARN_INT_CONVERSION = YES;
+				CLANG_WARN_NON_LITERAL_NULL_CONVERSION = YES;
+				CLANG_WARN_OBJC_LITERAL_CONVERSION = YES;
 				CLANG_WARN_OBJC_ROOT_CLASS = YES_ERROR;
+				CLANG_WARN_RANGE_LOOP_ANALYSIS = YES;
+				CLANG_WARN_STRICT_PROTOTYPES = YES;
 				CLANG_WARN_SUSPICIOUS_MOVE = YES;
 				CLANG_WARN_UNREACHABLE_CODE = YES;
 				CLANG_WARN__DUPLICATE_METHOD_MATCH = YES;
@@ -274,7 +286,8 @@
 				PRODUCT_NAME = "$(TARGET_NAME)";
 				SKIP_INSTALL = YES;
 				SWIFT_OPTIMIZATION_LEVEL = "-Onone";
-				SWIFT_VERSION = 3.0;
+				SWIFT_SWIFT3_OBJC_INFERENCE = On;
+				SWIFT_VERSION = 4.0;
 			};
 			name = Debug;
 		};
@@ -293,7 +306,8 @@
 				PRODUCT_BUNDLE_IDENTIFIER = "com.molabo.$(PRODUCT_NAME:rfc1034identifier)";
 				PRODUCT_NAME = "$(TARGET_NAME)";
 				SKIP_INSTALL = YES;
-				SWIFT_VERSION = 3.0;
+				SWIFT_SWIFT3_OBJC_INFERENCE = On;
+				SWIFT_VERSION = 4.0;
 			};
 			name = Release;
 		};
diff --git a/TouchVisualizer.xcodeproj/xcshareddata/xcschemes/TouchVisualizer.xcscheme b/TouchVisualizer.xcodeproj/xcshareddata/xcschemes/TouchVisualizer.xcscheme
index 1b1a6af..18f526c 100644
--- a/TouchVisualizer.xcodeproj/xcshareddata/xcschemes/TouchVisualizer.xcscheme
+++ b/TouchVisualizer.xcodeproj/xcshareddata/xcschemes/TouchVisualizer.xcscheme
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <Scheme
-   LastUpgradeVersion = "0800"
+   LastUpgradeVersion = "0900"
    version = "1.3">
    <BuildAction
       parallelizeBuildables = "YES"
@@ -40,6 +40,7 @@
       buildConfiguration = "Debug"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      language = ""
       shouldUseLaunchSchemeArgsEnv = "YES">
       <Testables>
          <TestableReference
@@ -69,6 +70,7 @@
       buildConfiguration = "Debug"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      language = ""
       launchStyle = "0"
       useCustomWorkingDirectory = "NO"
       ignoresPersistentStateOnLaunch = "NO"
diff --git a/TouchVisualizer/TouchView.swift b/TouchVisualizer/TouchView.swift
index ee53b8c..6c46ddb 100644
--- a/TouchVisualizer/TouchView.swift
+++ b/TouchVisualizer/TouchView.swift
@@ -90,7 +90,7 @@ final public class TouchView: UIImageView {
     }
     
     // MARK: - Update Functions
-    internal func update(_ timer: Timer) {
+    @objc internal func update(_ timer: Timer) {
         guard let startDate = startDate else { return }
         
         let interval = Date().timeIntervalSince(startDate)
diff --git a/TouchVisualizer/UIWindow+Swizzle.swift b/TouchVisualizer/UIWindow+Swizzle.swift
index 2f2bdcd..15bd0db 100644
--- a/TouchVisualizer/UIWindow+Swizzle.swift
+++ b/TouchVisualizer/UIWindow+Swizzle.swift
@@ -17,12 +17,12 @@ extension UIWindow {
 		
 		let sendEvent = class_getInstanceMethod(object_getClass(self), #selector(UIApplication.sendEvent(_:)))
 		let swizzledSendEvent = class_getInstanceMethod(object_getClass(self), #selector(UIWindow.swizzledSendEvent(_:)))
-		method_exchangeImplementations(sendEvent, swizzledSendEvent)
+		method_exchangeImplementations(sendEvent!, swizzledSendEvent!)
 		
 		isSwizzled = true
 	}
 	
-	public func swizzledSendEvent(_ event: UIEvent) {
+	@objc public func swizzledSendEvent(_ event: UIEvent) {
 		Visualizer.sharedInstance.handleEvent(event)
 		swizzledSendEvent(event)
 	}
diff --git a/circle.yml b/circle.yml
index d98d564..d662dfa 100644
--- a/circle.yml
+++ b/circle.yml
@@ -7,7 +7,7 @@ machine:
   environment:
     XCODE_SCHEME: ExampleTexts
   xcode:
-    version: "8.0"
+    version: "9.0"
 test:
   override:
     - xcodebuild test -scheme ExampleTests -destination 'platform=iOS Simulator,name=iPhone 6,OS=9.0'