diff --git a/DOFavoriteButton-DEMO/DOFavoriteButton-DEMO.xcodeproj/project.pbxproj b/DOFavoriteButton-DEMO/DOFavoriteButton-DEMO.xcodeproj/project.pbxproj
index 78be48a..6ff0138 100644
--- a/DOFavoriteButton-DEMO/DOFavoriteButton-DEMO.xcodeproj/project.pbxproj
+++ b/DOFavoriteButton-DEMO/DOFavoriteButton-DEMO.xcodeproj/project.pbxproj
@@ -209,10 +209,11 @@
 				TargetAttributes = {
 					4F60711A1B6366ED0058F570 = {
 						CreatedOnToolsVersion = 6.4;
-						LastSwiftMigration = 0800;
+						LastSwiftMigration = 0900;
 					};
 					4FBAA6FC1B4D807F00C8657F = {
 						CreatedOnToolsVersion = 6.4;
+						LastSwiftMigration = 0900;
 					};
 				};
 			};
@@ -325,7 +326,8 @@
 				PRODUCT_NAME = "$(TARGET_NAME)";
 				SKIP_INSTALL = YES;
 				SWIFT_OPTIMIZATION_LEVEL = "-Onone";
-				SWIFT_VERSION = 3.0;
+				SWIFT_SWIFT3_OBJC_INFERENCE = On;
+				SWIFT_VERSION = 4.0;
 				VERSIONING_SYSTEM = "apple-generic";
 				VERSION_INFO_PREFIX = "";
 			};
@@ -348,7 +350,8 @@
 				PRODUCT_BUNDLE_IDENTIFIER = "co.devlog.$(PRODUCT_NAME:rfc1034identifier)";
 				PRODUCT_NAME = "$(TARGET_NAME)";
 				SKIP_INSTALL = YES;
-				SWIFT_VERSION = 3.0;
+				SWIFT_SWIFT3_OBJC_INFERENCE = On;
+				SWIFT_VERSION = 4.0;
 				VERSIONING_SYSTEM = "apple-generic";
 				VERSION_INFO_PREFIX = "";
 			};
@@ -448,12 +451,14 @@
 			buildSettings = {
 				ALWAYS_EMBED_SWIFT_STANDARD_LIBRARIES = YES;
 				ASSETCATALOG_COMPILER_APPICON_NAME = AppIcon;
+				DEVELOPMENT_TEAM = "";
 				INFOPLIST_FILE = "DOFavoriteButton-DEMO/Info.plist";
 				IPHONEOS_DEPLOYMENT_TARGET = 8.0;
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks";
 				PRODUCT_BUNDLE_IDENTIFIER = "co.devlog.$(PRODUCT_NAME:rfc1034identifier)";
 				PRODUCT_NAME = "$(TARGET_NAME)";
-				SWIFT_VERSION = 3.0;
+				SWIFT_SWIFT3_OBJC_INFERENCE = On;
+				SWIFT_VERSION = 4.0;
 			};
 			name = Debug;
 		};
@@ -462,12 +467,14 @@
 			buildSettings = {
 				ALWAYS_EMBED_SWIFT_STANDARD_LIBRARIES = YES;
 				ASSETCATALOG_COMPILER_APPICON_NAME = AppIcon;
+				DEVELOPMENT_TEAM = "";
 				INFOPLIST_FILE = "DOFavoriteButton-DEMO/Info.plist";
 				IPHONEOS_DEPLOYMENT_TARGET = 8.0;
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks";
 				PRODUCT_BUNDLE_IDENTIFIER = "co.devlog.$(PRODUCT_NAME:rfc1034identifier)";
 				PRODUCT_NAME = "$(TARGET_NAME)";
-				SWIFT_VERSION = 3.0;
+				SWIFT_SWIFT3_OBJC_INFERENCE = On;
+				SWIFT_VERSION = 4.0;
 			};
 			name = Release;
 		};
diff --git a/DOFavoriteButton-DEMO/DOFavoriteButton-DEMO/Images.xcassets/AppIcon.appiconset/Contents.json b/DOFavoriteButton-DEMO/DOFavoriteButton-DEMO/Images.xcassets/AppIcon.appiconset/Contents.json
index 36d2c80..d8db8d6 100644
--- a/DOFavoriteButton-DEMO/DOFavoriteButton-DEMO/Images.xcassets/AppIcon.appiconset/Contents.json
+++ b/DOFavoriteButton-DEMO/DOFavoriteButton-DEMO/Images.xcassets/AppIcon.appiconset/Contents.json
@@ -1,5 +1,15 @@
 {
   "images" : [
+    {
+      "idiom" : "iphone",
+      "size" : "20x20",
+      "scale" : "2x"
+    },
+    {
+      "idiom" : "iphone",
+      "size" : "20x20",
+      "scale" : "3x"
+    },
     {
       "idiom" : "iphone",
       "size" : "29x29",
@@ -30,6 +40,16 @@
       "size" : "60x60",
       "scale" : "3x"
     },
+    {
+      "idiom" : "ipad",
+      "size" : "20x20",
+      "scale" : "1x"
+    },
+    {
+      "idiom" : "ipad",
+      "size" : "20x20",
+      "scale" : "2x"
+    },
     {
       "idiom" : "ipad",
       "size" : "29x29",
@@ -59,6 +79,16 @@
       "idiom" : "ipad",
       "size" : "76x76",
       "scale" : "2x"
+    },
+    {
+      "idiom" : "ipad",
+      "size" : "83.5x83.5",
+      "scale" : "2x"
+    },
+    {
+      "idiom" : "ios-marketing",
+      "size" : "1024x1024",
+      "scale" : "1x"
     }
   ],
   "info" : {
diff --git a/DOFavoriteButton-DEMO/DOFavoriteButton-DEMO/ViewController.swift b/DOFavoriteButton-DEMO/DOFavoriteButton-DEMO/ViewController.swift
index 70c3acd..a525b57 100644
--- a/DOFavoriteButton-DEMO/DOFavoriteButton-DEMO/ViewController.swift
+++ b/DOFavoriteButton-DEMO/DOFavoriteButton-DEMO/ViewController.swift
@@ -61,7 +61,7 @@ class ViewController: UIViewController {
         // Dispose of any resources that can be recreated.
     }
 
-    func tappedButton(sender: DOFavoriteButton) {
+    @objc func tappedButton(sender: DOFavoriteButton) {
         if sender.isSelected {
             sender.deselect()
         } else {
diff --git a/DOFavoriteButton/DOFavoriteButton.swift b/DOFavoriteButton/DOFavoriteButton.swift
index 47e6d9d..5c77f11 100644
--- a/DOFavoriteButton/DOFavoriteButton.swift
+++ b/DOFavoriteButton/DOFavoriteButton.swift
@@ -128,7 +128,7 @@ open class DOFavoriteButton: UIButton {
         circleShape.mask = circleMask
 
         let maskPath = UIBezierPath(rect: imageFrame)
-        maskPath.addArc(withCenter: imgCenterPoint, radius: 0.1, startAngle: CGFloat(0.0), endAngle: CGFloat(M_PI * 2), clockwise: true)
+        maskPath.addArc(withCenter: imgCenterPoint, radius: 0.1, startAngle: CGFloat(0.0), endAngle: CGFloat(Double.pi * 2), clockwise: true)
         circleMask.path = maskPath.cgPath
 
         //===============
@@ -155,7 +155,7 @@ open class DOFavoriteButton: UIButton {
             line.strokeStart = 0.0
             line.strokeEnd = 0.0
             line.opacity = 0.0
-            line.transform = CATransform3DMakeRotation(CGFloat(M_PI) / 5 * (CGFloat(i) * 2 + 1), 0.0, 0.0, 1.0)
+            line.transform = CATransform3DMakeRotation(CGFloat(Double.pi) / 5 * (CGFloat(i) * 2 + 1), 0.0, 0.0, 1.0)
             self.layer.addSublayer(line)
             lines.append(line)
         }
@@ -345,19 +345,19 @@ open class DOFavoriteButton: UIButton {
         self.addTarget(self, action: #selector(DOFavoriteButton.touchCancel(_:)), for: UIControlEvents.touchCancel)
     }
 
-    func touchDown(_ sender: DOFavoriteButton) {
+    @objc func touchDown(_ sender: DOFavoriteButton) {
         self.layer.opacity = 0.4
     }
-    func touchUpInside(_ sender: DOFavoriteButton) {
+    @objc func touchUpInside(_ sender: DOFavoriteButton) {
         self.layer.opacity = 1.0
     }
-    func touchDragExit(_ sender: DOFavoriteButton) {
+    @objc func touchDragExit(_ sender: DOFavoriteButton) {
         self.layer.opacity = 1.0
     }
-    func touchDragEnter(_ sender: DOFavoriteButton) {
+    @objc func touchDragEnter(_ sender: DOFavoriteButton) {
         self.layer.opacity = 0.4
     }
-    func touchCancel(_ sender: DOFavoriteButton) {
+    @objc func touchCancel(_ sender: DOFavoriteButton) {
         self.layer.opacity = 1.0
     }